Here's why:
* Collective nouns are words that describe groups of things, often with a sense of unity or purpose. Examples include a flock of birds, a herd of cows, or a pack of wolves.
* Chicken grains are a collection of individual grains used as food for chickens. They don't typically act as a unified entity.
Instead of a collective noun, you could use phrases like:
* A bag of chicken feed
* A bowl of chicken grains
* A supply of chicken feed
Let me know if you have any other questions!