Why is my rooster chewing his tail feathers?

[aart]

I've
Quote: I like to feed an 'all flock' 20% protein crumble to all ages and genders. Makes life much simpler to store and distribute one type of chow that everyone can eat and have calcium available at all times for the layers, oyster shell mixed with rinsed, dried, crushed chicken egg shells in a separate container.

The higher protein crumble offsets the 8% protein scratch grains and other kitchen/garden scraps I like to offer.