diff --git a/src/animaltrack/events/__init__.py b/src/animaltrack/events/__init__.py
index d79dd54..b551df5 100644
--- a/src/animaltrack/events/__init__.py
+++ b/src/animaltrack/events/__init__.py
@@ -1,7 +1,36 @@
 # ABOUTME: Events package for event sourcing infrastructure.
-# ABOUTME: Provides event types, store, and related exceptions.
+# ABOUTME: Provides event types, store, payloads, and related exceptions.
 
+from animaltrack.events.enums import (
+    AnimalStatus,
+    LifeStage,
+    Origin,
+    Outcome,
+    ReproStatus,
+    Sex,
+)
 from animaltrack.events.exceptions import ClockSkewError, DuplicateNonceError
+from animaltrack.events.payloads import (
+    AnimalAttributesUpdatedPayload,
+    AnimalCohortCreatedPayload,
+    AnimalMergedPayload,
+    AnimalMovedPayload,
+    AnimalOutcomePayload,
+    AnimalPromotedPayload,
+    AnimalStatusCorrectedPayload,
+    AnimalTagEndedPayload,
+    AnimalTaggedPayload,
+    AttributeSet,
+    FeedGivenPayload,
+    FeedPurchasedPayload,
+    HatchRecordedPayload,
+    LocationArchivedPayload,
+    LocationCreatedPayload,
+    LocationRenamedPayload,
+    ProductCollectedPayload,
+    ProductSoldPayload,
+    YieldItem,
+)
 from animaltrack.events.store import EventStore
 from animaltrack.events.types import (
     ALL_EVENT_TYPES,
@@ -23,6 +52,7 @@ from animaltrack.events.types import (
     PRODUCT_COLLECTED,
     PRODUCT_SOLD,
 )
+from animaltrack.events.validation import normalize_tag, validate_ulid, validate_ulid_list
 
 __all__ = [
     # Event types
@@ -44,9 +74,44 @@ __all__ = [
     "FEED_PURCHASED",
     "FEED_GIVEN",
     "ALL_EVENT_TYPES",
+    # Enums
+    "Sex",
+    "ReproStatus",
+    "LifeStage",
+    "AnimalStatus",
+    "Origin",
+    "Outcome",
     # Exceptions
     "ClockSkewError",
     "DuplicateNonceError",
     # Store
     "EventStore",
+    # Validation
+    "normalize_tag",
+    "validate_ulid",
+    "validate_ulid_list",
+    # Payloads - Location
+    "LocationCreatedPayload",
+    "LocationRenamedPayload",
+    "LocationArchivedPayload",
+    # Payloads - Animal
+    "AnimalCohortCreatedPayload",
+    "AnimalPromotedPayload",
+    "AnimalMovedPayload",
+    "AnimalAttributesUpdatedPayload",
+    "AnimalTaggedPayload",
+    "AnimalTagEndedPayload",
+    "HatchRecordedPayload",
+    "AnimalOutcomePayload",
+    "AnimalMergedPayload",
+    "AnimalStatusCorrectedPayload",
+    # Payloads - Product
+    "ProductCollectedPayload",
+    "ProductSoldPayload",
+    # Payloads - Feed
+    "FeedPurchasedPayload",
+    "FeedGivenPayload",
+    # Payloads - Helper models
+    "YieldItem",
+    "AttributeSet",
 ]
diff --git a/src/animaltrack/events/enums.py b/src/animaltrack/events/enums.py
new file mode 100644
index 0000000..1a0cba4
--- /dev/null
+++ b/src/animaltrack/events/enums.py
@@ -0,0 +1,59 @@
+# ABOUTME: Enums for event payloads and animal attributes.
+# ABOUTME: Defines Sex, ReproStatus, LifeStage, AnimalStatus, Origin, and Outcome.
+
+from enum import Enum
+
+
+class Sex(str, Enum):
+    """Biological sex of an animal."""
+
+    MALE = "male"
+    FEMALE = "female"
+    UNKNOWN = "unknown"
+
+
+class ReproStatus(str, Enum):
+    """Reproductive status of an animal."""
+
+    INTACT = "intact"
+    WETHER = "wether"
+    SPAYED = "spayed"
+    UNKNOWN = "unknown"
+
+
+class LifeStage(str, Enum):
+    """Life stage of an animal."""
+
+    HATCHLING = "hatchling"
+    JUVENILE = "juvenile"
+    SUBADULT = "subadult"
+    ADULT = "adult"
+
+
+class AnimalStatus(str, Enum):
+    """Current status of an animal."""
+
+    ALIVE = "alive"
+    DEAD = "dead"
+    HARVESTED = "harvested"
+    SOLD = "sold"
+    MERGED_INTO = "merged_into"
+
+
+class Origin(str, Enum):
+    """Origin of an animal (how it came to the farm)."""
+
+    HATCHED = "hatched"
+    PURCHASED = "purchased"
+    RESCUED = "rescued"
+    UNKNOWN = "unknown"
+
+
+class Outcome(str, Enum):
+    """Outcome type for animal lifecycle events."""
+
+    DEATH = "death"
+    HARVEST = "harvest"
+    SOLD = "sold"
+    PREDATOR_LOSS = "predator_loss"
+    UNKNOWN = "unknown"
diff --git a/src/animaltrack/events/payloads.py b/src/animaltrack/events/payloads.py
new file mode 100644
index 0000000..0b947e8
--- /dev/null
+++ b/src/animaltrack/events/payloads.py
@@ -0,0 +1,370 @@
+# ABOUTME: Pydantic models for all 17 event payload types.
+# ABOUTME: Validates event data before storage per spec §6.
+
+from typing import Literal
+
+from pydantic import BaseModel, Field, field_validator
+
+from animaltrack.events.enums import (
+    AnimalStatus,
+    LifeStage,
+    Origin,
+    Outcome,
+    ReproStatus,
+    Sex,
+)
+from animaltrack.events.validation import normalize_tag, validate_ulid
+
+# =============================================================================
+# Helper Models
+# =============================================================================
+
+
+class YieldItem(BaseModel):
+    """A product yield from an animal outcome (harvest)."""
+
+    product_code: str
+    unit: Literal["piece", "kg"]
+    quantity: int = Field(..., ge=1)
+    weight_kg: float | None = None
+    notes: str | None = None
+
+
+class AttributeSet(BaseModel):
+    """Set of animal attributes that can be updated."""
+
+    sex: Sex | None = None
+    life_stage: LifeStage | None = None
+    repro_status: ReproStatus | None = None
+
+
+# =============================================================================
+# Location Event Payloads (3)
+# =============================================================================
+
+
+class LocationCreatedPayload(BaseModel):
+    """Payload for LocationCreated event."""
+
+    location_id: str = Field(..., min_length=26, max_length=26)
+    name: str
+
+    @field_validator("location_id")
+    @classmethod
+    def validate_location_ulid(cls, v: str) -> str:
+        """Validate location_id is a valid ULID."""
+        return validate_ulid(v)
+
+
+class LocationRenamedPayload(BaseModel):
+    """Payload for LocationRenamed event."""
+
+    location_id: str = Field(..., min_length=26, max_length=26)
+    new_name: str
+
+    @field_validator("location_id")
+    @classmethod
+    def validate_location_ulid(cls, v: str) -> str:
+        """Validate location_id is a valid ULID."""
+        return validate_ulid(v)
+
+
+class LocationArchivedPayload(BaseModel):
+    """Payload for LocationArchived event."""
+
+    location_id: str = Field(..., min_length=26, max_length=26)
+
+    @field_validator("location_id")
+    @classmethod
+    def validate_location_ulid(cls, v: str) -> str:
+        """Validate location_id is a valid ULID."""
+        return validate_ulid(v)
+
+
+# =============================================================================
+# Animal Event Payloads (10)
+# =============================================================================
+
+
+class AnimalCohortCreatedPayload(BaseModel):
+    """Payload for AnimalCohortCreated event."""
+
+    species: Literal["duck", "goose"]
+    count: int = Field(..., ge=1)
+    life_stage: LifeStage
+    sex: Sex = Sex.UNKNOWN
+    location_id: str = Field(..., min_length=26, max_length=26)
+    origin: Origin
+    notes: str | None = None
+
+    @field_validator("location_id")
+    @classmethod
+    def validate_location_ulid(cls, v: str) -> str:
+        """Validate location_id is a valid ULID."""
+        return validate_ulid(v)
+
+
+class AnimalPromotedPayload(BaseModel):
+    """Payload for AnimalPromoted event."""
+
+    animal_id: str = Field(..., min_length=26, max_length=26)
+    nickname: str | None = None
+    sex: Sex | None = None
+    repro_status: ReproStatus | None = None
+    distinguishing_traits: str | None = None
+    notes: str | None = None
+
+    @field_validator("animal_id")
+    @classmethod
+    def validate_animal_ulid(cls, v: str) -> str:
+        """Validate animal_id is a valid ULID."""
+        return validate_ulid(v)
+
+
+class AnimalMovedPayload(BaseModel):
+    """Payload for AnimalMoved event."""
+
+    to_location_id: str = Field(..., min_length=26, max_length=26)
+    resolved_ids: list[str] = Field(..., min_length=1)
+    notes: str | None = None
+
+    @field_validator("to_location_id")
+    @classmethod
+    def validate_location_ulid(cls, v: str) -> str:
+        """Validate to_location_id is a valid ULID."""
+        return validate_ulid(v)
+
+    @field_validator("resolved_ids")
+    @classmethod
+    def validate_resolved_ulids(cls, v: list[str]) -> list[str]:
+        """Validate all resolved_ids are valid ULIDs."""
+        for i, ulid in enumerate(v):
+            if len(ulid) != 26:
+                msg = f"resolved_ids[{i}] must be 26 characters"
+                raise ValueError(msg)
+        return v
+
+
+class AnimalAttributesUpdatedPayload(BaseModel):
+    """Payload for AnimalAttributesUpdated event."""
+
+    resolved_ids: list[str] = Field(..., min_length=1)
+    set: AttributeSet
+    notes: str | None = None
+
+    @field_validator("resolved_ids")
+    @classmethod
+    def validate_resolved_ulids(cls, v: list[str]) -> list[str]:
+        """Validate all resolved_ids are valid ULIDs."""
+        for i, ulid in enumerate(v):
+            if len(ulid) != 26:
+                msg = f"resolved_ids[{i}] must be 26 characters"
+                raise ValueError(msg)
+        return v
+
+
+class AnimalTaggedPayload(BaseModel):
+    """Payload for AnimalTagged event."""
+
+    resolved_ids: list[str] = Field(..., min_length=1)
+    tag: str
+    notes: str | None = None
+
+    @field_validator("resolved_ids")
+    @classmethod
+    def validate_resolved_ulids(cls, v: list[str]) -> list[str]:
+        """Validate all resolved_ids are valid ULIDs."""
+        for i, ulid in enumerate(v):
+            if len(ulid) != 26:
+                msg = f"resolved_ids[{i}] must be 26 characters"
+                raise ValueError(msg)
+        return v
+
+    @field_validator("tag")
+    @classmethod
+    def normalize_tag_value(cls, v: str) -> str:
+        """Normalize the tag per spec §20."""
+        return normalize_tag(v)
+
+
+class AnimalTagEndedPayload(BaseModel):
+    """Payload for AnimalTagEnded event."""
+
+    resolved_ids: list[str] = Field(..., min_length=1)
+    tag: str
+    notes: str | None = None
+
+    @field_validator("resolved_ids")
+    @classmethod
+    def validate_resolved_ulids(cls, v: list[str]) -> list[str]:
+        """Validate all resolved_ids are valid ULIDs."""
+        for i, ulid in enumerate(v):
+            if len(ulid) != 26:
+                msg = f"resolved_ids[{i}] must be 26 characters"
+                raise ValueError(msg)
+        return v
+
+    @field_validator("tag")
+    @classmethod
+    def normalize_tag_value(cls, v: str) -> str:
+        """Normalize the tag per spec §20."""
+        return normalize_tag(v)
+
+
+class HatchRecordedPayload(BaseModel):
+    """Payload for HatchRecorded event."""
+
+    species: Literal["duck", "goose"]
+    location_id: str = Field(..., min_length=26, max_length=26)
+    assigned_brood_location_id: str | None = None
+    hatched_live: int = Field(..., ge=1)
+    notes: str | None = None
+
+    @field_validator("location_id")
+    @classmethod
+    def validate_location_ulid(cls, v: str) -> str:
+        """Validate location_id is a valid ULID."""
+        return validate_ulid(v)
+
+    @field_validator("assigned_brood_location_id")
+    @classmethod
+    def validate_brood_location_ulid(cls, v: str | None) -> str | None:
+        """Validate assigned_brood_location_id is a valid ULID if provided."""
+        if v is not None:
+            return validate_ulid(v)
+        return v
+
+
+class AnimalOutcomePayload(BaseModel):
+    """Payload for AnimalOutcome event."""
+
+    outcome: Outcome
+    resolved_ids: list[str] = Field(..., min_length=1)
+    reason: str | None = None
+    yield_items: list[YieldItem] | None = None
+    notes: str | None = None
+
+    @field_validator("resolved_ids")
+    @classmethod
+    def validate_resolved_ulids(cls, v: list[str]) -> list[str]:
+        """Validate all resolved_ids are valid ULIDs."""
+        for i, ulid in enumerate(v):
+            if len(ulid) != 26:
+                msg = f"resolved_ids[{i}] must be 26 characters"
+                raise ValueError(msg)
+        return v
+
+
+class AnimalMergedPayload(BaseModel):
+    """Payload for AnimalMerged event."""
+
+    survivor_animal_id: str = Field(..., min_length=26, max_length=26)
+    merged_animal_ids: list[str] = Field(..., min_length=1)
+    notes: str | None = None
+
+    @field_validator("survivor_animal_id")
+    @classmethod
+    def validate_survivor_ulid(cls, v: str) -> str:
+        """Validate survivor_animal_id is a valid ULID."""
+        return validate_ulid(v)
+
+    @field_validator("merged_animal_ids")
+    @classmethod
+    def validate_merged_ulids(cls, v: list[str]) -> list[str]:
+        """Validate all merged_animal_ids are valid ULIDs."""
+        for i, ulid in enumerate(v):
+            if len(ulid) != 26:
+                msg = f"merged_animal_ids[{i}] must be 26 characters"
+                raise ValueError(msg)
+        return v
+
+
+class AnimalStatusCorrectedPayload(BaseModel):
+    """Payload for AnimalStatusCorrected event (admin-only)."""
+
+    resolved_ids: list[str] = Field(..., min_length=1)
+    new_status: AnimalStatus
+    reason: str  # Required for audit trail
+    notes: str | None = None
+
+    @field_validator("resolved_ids")
+    @classmethod
+    def validate_resolved_ulids(cls, v: list[str]) -> list[str]:
+        """Validate all resolved_ids are valid ULIDs."""
+        for i, ulid in enumerate(v):
+            if len(ulid) != 26:
+                msg = f"resolved_ids[{i}] must be 26 characters"
+                raise ValueError(msg)
+        return v
+
+
+# =============================================================================
+# Product Event Payloads (2)
+# =============================================================================
+
+
+class ProductCollectedPayload(BaseModel):
+    """Payload for ProductCollected event."""
+
+    location_id: str = Field(..., min_length=26, max_length=26)
+    product_code: str
+    quantity: int = Field(..., ge=1)
+    resolved_ids: list[str] = Field(..., min_length=1)
+    notes: str | None = None
+
+    @field_validator("location_id")
+    @classmethod
+    def validate_location_ulid(cls, v: str) -> str:
+        """Validate location_id is a valid ULID."""
+        return validate_ulid(v)
+
+    @field_validator("resolved_ids")
+    @classmethod
+    def validate_resolved_ulids(cls, v: list[str]) -> list[str]:
+        """Validate all resolved_ids are valid ULIDs."""
+        for i, ulid in enumerate(v):
+            if len(ulid) != 26:
+                msg = f"resolved_ids[{i}] must be 26 characters"
+                raise ValueError(msg)
+        return v
+
+
+class ProductSoldPayload(BaseModel):
+    """Payload for ProductSold event."""
+
+    product_code: str
+    quantity: int = Field(..., ge=1)
+    total_price_cents: int = Field(..., ge=0)
+    buyer: str | None = None
+    notes: str | None = None
+
+
+# =============================================================================
+# Feed Event Payloads (2)
+# =============================================================================
+
+
+class FeedPurchasedPayload(BaseModel):
+    """Payload for FeedPurchased event."""
+
+    feed_type_code: str
+    bag_size_kg: int = Field(..., ge=1)
+    bags_count: int = Field(..., ge=1)
+    bag_price_cents: int = Field(..., ge=0)
+    vendor: str | None = None
+    notes: str | None = None
+
+
+class FeedGivenPayload(BaseModel):
+    """Payload for FeedGiven event."""
+
+    location_id: str = Field(..., min_length=26, max_length=26)
+    feed_type_code: str
+    amount_kg: int = Field(..., ge=1)
+    notes: str | None = None
+
+    @field_validator("location_id")
+    @classmethod
+    def validate_location_ulid(cls, v: str) -> str:
+        """Validate location_id is a valid ULID."""
+        return validate_ulid(v)
diff --git a/src/animaltrack/events/validation.py b/src/animaltrack/events/validation.py
new file mode 100644
index 0000000..1ac1d61
--- /dev/null
+++ b/src/animaltrack/events/validation.py
@@ -0,0 +1,76 @@
+# ABOUTME: Validation utilities for event payloads.
+# ABOUTME: Includes tag normalization per spec §20 and ULID validators.
+
+import re
+
+
+def normalize_tag(tag: str) -> str:
+    """Normalize a tag per spec §20.
+
+    Normalization rules:
+    - Convert to lowercase
+    - Trim leading/trailing whitespace
+    - Replace spaces with hyphens
+    - Keep only valid characters [a-z0-9:_-]
+    - Truncate to max 32 characters
+    - Raise ValueError if empty after normalization
+
+    Args:
+        tag: The raw tag string to normalize.
+
+    Returns:
+        The normalized tag string.
+
+    Raises:
+        ValueError: If the tag is empty after normalization.
+    """
+    # Trim and lowercase
+    tag = tag.strip().lower()
+    # Spaces to hyphens
+    tag = tag.replace(" ", "-")
+    # Keep only valid chars: a-z, 0-9, colon, underscore, hyphen
+    tag = re.sub(r"[^a-z0-9:_-]", "", tag)
+    # Max 32 chars
+    tag = tag[:32]
+    # Check for empty
+    if not tag:
+        msg = "Tag is empty after normalization"
+        raise ValueError(msg)
+    return tag
+
+
+def validate_ulid(value: str) -> str:
+    """Validate that a value is a 26-character ULID.
+
+    Args:
+        value: The string to validate.
+
+    Returns:
+        The validated string.
+
+    Raises:
+        ValueError: If the value is not exactly 26 characters.
+    """
+    if len(value) != 26:
+        msg = f"ULID must be exactly 26 characters, got {len(value)}"
+        raise ValueError(msg)
+    return value
+
+
+def validate_ulid_list(values: list[str]) -> list[str]:
+    """Validate that all values in a list are 26-character ULIDs.
+
+    Args:
+        values: The list of strings to validate.
+
+    Returns:
+        The validated list.
+
+    Raises:
+        ValueError: If any value is not exactly 26 characters.
+    """
+    for i, value in enumerate(values):
+        if len(value) != 26:
+            msg = f"ULID at index {i} must be exactly 26 characters, got {len(value)}"
+            raise ValueError(msg)
+    return values
diff --git a/tests/test_event_payloads.py b/tests/test_event_payloads.py
new file mode 100644
index 0000000..be509d2
--- /dev/null
+++ b/tests/test_event_payloads.py
@@ -0,0 +1,420 @@
+# ABOUTME: Tests for event payload models and tag normalization.
+# ABOUTME: Validates all 17 event payload types and the normalize_tag function.
+
+import pytest
+from pydantic import ValidationError
+
+from animaltrack.events.enums import (
+    AnimalStatus,
+    LifeStage,
+    Origin,
+    Outcome,
+    ReproStatus,
+    Sex,
+)
+from animaltrack.events.validation import normalize_tag
+
+
+class TestTagNormalization:
+    """Tests for tag normalization per spec §20."""
+
+    def test_lowercase_conversion(self):
+        """Tags are converted to lowercase."""
+        assert normalize_tag("ABC") == "abc"
+        assert normalize_tag("MyTag") == "mytag"
+
+    def test_trim_whitespace(self):
+        """Leading and trailing whitespace is trimmed."""
+        assert normalize_tag("  tag  ") == "tag"
+        assert normalize_tag("\ttag\n") == "tag"
+
+    def test_spaces_to_hyphens(self):
+        """Internal spaces are converted to hyphens."""
+        assert normalize_tag("my tag") == "my-tag"
+        assert normalize_tag("my  tag") == "my--tag"
+
+    def test_removes_invalid_chars(self):
+        """Invalid characters are removed."""
+        assert normalize_tag("tag@#$!") == "tag"
+        assert normalize_tag("hello.world") == "helloworld"
+        assert normalize_tag("tag(1)") == "tag1"
+
+    def test_keeps_valid_chars(self):
+        """Valid characters [a-z0-9:_-] are preserved."""
+        assert normalize_tag("tag:sub_item-1") == "tag:sub_item-1"
+        assert normalize_tag("layer:duck_2024") == "layer:duck_2024"
+
+    def test_max_length_32(self):
+        """Tags are truncated to 32 characters."""
+        long_tag = "a" * 50
+        result = normalize_tag(long_tag)
+        assert len(result) == 32
+        assert result == "a" * 32
+
+    def test_empty_after_normalization_raises(self):
+        """Empty tag after normalization raises ValueError."""
+        with pytest.raises(ValueError, match="empty after normalization"):
+            normalize_tag("")
+        with pytest.raises(ValueError, match="empty after normalization"):
+            normalize_tag("   ")
+        with pytest.raises(ValueError, match="empty after normalization"):
+            normalize_tag("@#$%")
+
+
+class TestEnums:
+    """Tests for event-related enums."""
+
+    def test_sex_values(self):
+        """Sex enum has correct values."""
+        assert Sex.MALE.value == "male"
+        assert Sex.FEMALE.value == "female"
+        assert Sex.UNKNOWN.value == "unknown"
+
+    def test_repro_status_values(self):
+        """ReproStatus enum has correct values."""
+        assert ReproStatus.INTACT.value == "intact"
+        assert ReproStatus.WETHER.value == "wether"
+        assert ReproStatus.SPAYED.value == "spayed"
+        assert ReproStatus.UNKNOWN.value == "unknown"
+
+    def test_life_stage_values(self):
+        """LifeStage enum has correct values."""
+        assert LifeStage.HATCHLING.value == "hatchling"
+        assert LifeStage.JUVENILE.value == "juvenile"
+        assert LifeStage.SUBADULT.value == "subadult"
+        assert LifeStage.ADULT.value == "adult"
+
+    def test_animal_status_values(self):
+        """AnimalStatus enum has correct values."""
+        assert AnimalStatus.ALIVE.value == "alive"
+        assert AnimalStatus.DEAD.value == "dead"
+        assert AnimalStatus.HARVESTED.value == "harvested"
+        assert AnimalStatus.SOLD.value == "sold"
+        assert AnimalStatus.MERGED_INTO.value == "merged_into"
+
+    def test_origin_values(self):
+        """Origin enum has correct values."""
+        assert Origin.HATCHED.value == "hatched"
+        assert Origin.PURCHASED.value == "purchased"
+        assert Origin.RESCUED.value == "rescued"
+        assert Origin.UNKNOWN.value == "unknown"
+
+    def test_outcome_values(self):
+        """Outcome enum has correct values."""
+        assert Outcome.DEATH.value == "death"
+        assert Outcome.HARVEST.value == "harvest"
+        assert Outcome.SOLD.value == "sold"
+        assert Outcome.PREDATOR_LOSS.value == "predator_loss"
+        assert Outcome.UNKNOWN.value == "unknown"
+
+
+# Import payloads after validation is created
+# These tests will initially fail until payloads.py is implemented
+
+
+class TestLocationPayloads:
+    """Tests for location event payloads."""
+
+    def test_location_created_valid(self):
+        """Valid LocationCreatedPayload is accepted."""
+        from animaltrack.events.payloads import LocationCreatedPayload
+
+        payload = LocationCreatedPayload(
+            location_id="01ARZ3NDEKTSV4RRFFQ69G5FAV",
+            name="Strip 1",
+        )
+        assert payload.location_id == "01ARZ3NDEKTSV4RRFFQ69G5FAV"
+        assert payload.name == "Strip 1"
+
+    def test_location_created_invalid_ulid(self):
+        """LocationCreatedPayload rejects invalid ULID."""
+        from animaltrack.events.payloads import LocationCreatedPayload
+
+        with pytest.raises(ValidationError):
+            LocationCreatedPayload(
+                location_id="short",
+                name="Strip 1",
+            )
+
+    def test_location_renamed_valid(self):
+        """Valid LocationRenamedPayload is accepted."""
+        from animaltrack.events.payloads import LocationRenamedPayload
+
+        payload = LocationRenamedPayload(
+            location_id="01ARZ3NDEKTSV4RRFFQ69G5FAV",
+            new_name="Strip 1 - Renamed",
+        )
+        assert payload.new_name == "Strip 1 - Renamed"
+
+    def test_location_archived_valid(self):
+        """Valid LocationArchivedPayload is accepted."""
+        from animaltrack.events.payloads import LocationArchivedPayload
+
+        payload = LocationArchivedPayload(
+            location_id="01ARZ3NDEKTSV4RRFFQ69G5FAV",
+        )
+        assert payload.location_id == "01ARZ3NDEKTSV4RRFFQ69G5FAV"
+
+
+class TestAnimalCohortPayload:
+    """Tests for AnimalCohortCreatedPayload."""
+
+    def test_valid_cohort(self):
+        """Valid AnimalCohortCreatedPayload is accepted."""
+        from animaltrack.events.payloads import AnimalCohortCreatedPayload
+
+        payload = AnimalCohortCreatedPayload(
+            species="duck",
+            count=10,
+            life_stage=LifeStage.ADULT,
+            location_id="01ARZ3NDEKTSV4RRFFQ69G5FAV",
+            origin=Origin.PURCHASED,
+        )
+        assert payload.count == 10
+        assert payload.sex == Sex.UNKNOWN  # Default
+
+    def test_count_must_be_positive(self):
+        """count must be >= 1."""
+        from animaltrack.events.payloads import AnimalCohortCreatedPayload
+
+        with pytest.raises(ValidationError):
+            AnimalCohortCreatedPayload(
+                species="duck",
+                count=0,
+                life_stage=LifeStage.ADULT,
+                location_id="01ARZ3NDEKTSV4RRFFQ69G5FAV",
+                origin=Origin.PURCHASED,
+            )
+
+    def test_invalid_species_rejected(self):
+        """Invalid species value is rejected."""
+        from animaltrack.events.payloads import AnimalCohortCreatedPayload
+
+        with pytest.raises(ValidationError):
+            AnimalCohortCreatedPayload(
+                species="cow",  # Not duck or goose
+                count=10,
+                life_stage=LifeStage.ADULT,
+                location_id="01ARZ3NDEKTSV4RRFFQ69G5FAV",
+                origin=Origin.PURCHASED,
+            )
+
+    def test_sex_defaults_to_unknown(self):
+        """sex defaults to unknown when not provided."""
+        from animaltrack.events.payloads import AnimalCohortCreatedPayload
+
+        payload = AnimalCohortCreatedPayload(
+            species="goose",
+            count=5,
+            life_stage=LifeStage.JUVENILE,
+            location_id="01ARZ3NDEKTSV4RRFFQ69G5FAV",
+            origin=Origin.HATCHED,
+        )
+        assert payload.sex == Sex.UNKNOWN
+
+
+class TestAnimalMovedPayload:
+    """Tests for AnimalMovedPayload."""
+
+    def test_valid_move(self):
+        """Valid AnimalMovedPayload is accepted."""
+        from animaltrack.events.payloads import AnimalMovedPayload
+
+        payload = AnimalMovedPayload(
+            to_location_id="01ARZ3NDEKTSV4RRFFQ69G5FAV",
+            resolved_ids=["01ARZ3NDEKTSV4RRFFQ69G5FAV", "01ARZ3NDEKTSV4RRFFQ69G5FAW"],
+        )
+        assert len(payload.resolved_ids) == 2
+
+    def test_empty_resolved_ids_rejected(self):
+        """resolved_ids must not be empty."""
+        from animaltrack.events.payloads import AnimalMovedPayload
+
+        with pytest.raises(ValidationError):
+            AnimalMovedPayload(
+                to_location_id="01ARZ3NDEKTSV4RRFFQ69G5FAV",
+                resolved_ids=[],
+            )
+
+    def test_invalid_location_rejected(self):
+        """Invalid location ULID is rejected."""
+        from animaltrack.events.payloads import AnimalMovedPayload
+
+        with pytest.raises(ValidationError):
+            AnimalMovedPayload(
+                to_location_id="short",
+                resolved_ids=["01ARZ3NDEKTSV4RRFFQ69G5FAV"],
+            )
+
+
+class TestAnimalTaggedPayload:
+    """Tests for AnimalTaggedPayload."""
+
+    def test_valid_tag(self):
+        """Valid AnimalTaggedPayload is accepted."""
+        from animaltrack.events.payloads import AnimalTaggedPayload
+
+        payload = AnimalTaggedPayload(
+            resolved_ids=["01ARZ3NDEKTSV4RRFFQ69G5FAV"],
+            tag="layer:prime",
+        )
+        assert payload.tag == "layer:prime"
+
+    def test_tag_normalized_on_validation(self):
+        """Tag is normalized during validation."""
+        from animaltrack.events.payloads import AnimalTaggedPayload
+
+        payload = AnimalTaggedPayload(
+            resolved_ids=["01ARZ3NDEKTSV4RRFFQ69G5FAV"],
+            tag="  Layer Prime  ",
+        )
+        assert payload.tag == "layer-prime"
+
+
+class TestProductPayloads:
+    """Tests for product event payloads."""
+
+    def test_product_collected_valid(self):
+        """Valid ProductCollectedPayload is accepted."""
+        from animaltrack.events.payloads import ProductCollectedPayload
+
+        payload = ProductCollectedPayload(
+            location_id="01ARZ3NDEKTSV4RRFFQ69G5FAV",
+            product_code="egg.duck",
+            quantity=12,
+            resolved_ids=["01ARZ3NDEKTSV4RRFFQ69G5FAV"],
+        )
+        assert payload.quantity == 12
+
+    def test_quantity_must_be_positive(self):
+        """quantity must be >= 1."""
+        from animaltrack.events.payloads import ProductCollectedPayload
+
+        with pytest.raises(ValidationError):
+            ProductCollectedPayload(
+                location_id="01ARZ3NDEKTSV4RRFFQ69G5FAV",
+                product_code="egg.duck",
+                quantity=0,
+                resolved_ids=["01ARZ3NDEKTSV4RRFFQ69G5FAV"],
+            )
+
+    def test_product_sold_valid(self):
+        """Valid ProductSoldPayload is accepted."""
+        from animaltrack.events.payloads import ProductSoldPayload
+
+        payload = ProductSoldPayload(
+            product_code="egg.duck",
+            quantity=30,
+            total_price_cents=1500,  # €15.00
+        )
+        assert payload.total_price_cents == 1500
+
+    def test_price_cents_non_negative(self):
+        """total_price_cents must be >= 0."""
+        from animaltrack.events.payloads import ProductSoldPayload
+
+        with pytest.raises(ValidationError):
+            ProductSoldPayload(
+                product_code="egg.duck",
+                quantity=30,
+                total_price_cents=-100,
+            )
+
+
+class TestFeedPayloads:
+    """Tests for feed event payloads."""
+
+    def test_feed_purchased_valid(self):
+        """Valid FeedPurchasedPayload is accepted."""
+        from animaltrack.events.payloads import FeedPurchasedPayload
+
+        payload = FeedPurchasedPayload(
+            feed_type_code="layer",
+            bag_size_kg=20,
+            bags_count=5,
+            bag_price_cents=2500,  # €25.00 per bag
+        )
+        assert payload.bags_count == 5
+
+    def test_feed_given_valid(self):
+        """Valid FeedGivenPayload is accepted."""
+        from animaltrack.events.payloads import FeedGivenPayload
+
+        payload = FeedGivenPayload(
+            location_id="01ARZ3NDEKTSV4RRFFQ69G5FAV",
+            feed_type_code="layer",
+            amount_kg=2,
+        )
+        assert payload.amount_kg == 2
+
+    def test_amount_kg_must_be_positive(self):
+        """amount_kg must be >= 1."""
+        from animaltrack.events.payloads import FeedGivenPayload
+
+        with pytest.raises(ValidationError):
+            FeedGivenPayload(
+                location_id="01ARZ3NDEKTSV4RRFFQ69G5FAV",
+                feed_type_code="layer",
+                amount_kg=0,
+            )
+
+
+class TestAnimalOutcomePayload:
+    """Tests for AnimalOutcomePayload."""
+
+    def test_valid_outcome(self):
+        """Valid AnimalOutcomePayload is accepted."""
+        from animaltrack.events.payloads import AnimalOutcomePayload
+
+        payload = AnimalOutcomePayload(
+            outcome=Outcome.HARVEST,
+            resolved_ids=["01ARZ3NDEKTSV4RRFFQ69G5FAV"],
+        )
+        assert payload.outcome == Outcome.HARVEST
+
+    def test_yield_items_optional(self):
+        """yield_items is optional."""
+        from animaltrack.events.payloads import AnimalOutcomePayload
+
+        payload = AnimalOutcomePayload(
+            outcome=Outcome.DEATH,
+            resolved_ids=["01ARZ3NDEKTSV4RRFFQ69G5FAV"],
+            reason="Natural causes",
+        )
+        assert payload.yield_items is None
+
+    def test_invalid_outcome_rejected(self):
+        """Invalid outcome value is rejected."""
+        from animaltrack.events.payloads import AnimalOutcomePayload
+
+        with pytest.raises(ValidationError):
+            AnimalOutcomePayload(
+                outcome="invalid",
+                resolved_ids=["01ARZ3NDEKTSV4RRFFQ69G5FAV"],
+            )
+
+
+class TestAnimalStatusCorrectedPayload:
+    """Tests for AnimalStatusCorrectedPayload."""
+
+    def test_reason_required(self):
+        """reason is required for status corrections."""
+        from animaltrack.events.payloads import AnimalStatusCorrectedPayload
+
+        with pytest.raises(ValidationError):
+            AnimalStatusCorrectedPayload(
+                resolved_ids=["01ARZ3NDEKTSV4RRFFQ69G5FAV"],
+                new_status=AnimalStatus.ALIVE,
+                # Missing reason
+            )
+
+    def test_valid_status_correction(self):
+        """Valid AnimalStatusCorrectedPayload is accepted."""
+        from animaltrack.events.payloads import AnimalStatusCorrectedPayload
+
+        payload = AnimalStatusCorrectedPayload(
+            resolved_ids=["01ARZ3NDEKTSV4RRFFQ69G5FAV"],
+            new_status=AnimalStatus.ALIVE,
+            reason="Animal was incorrectly marked as dead",
+        )
+        assert payload.reason == "Animal was incorrectly marked as dead"