Chicken Diet - What To Feed Pet Chickens | RSPCA - RSPCA
Chickens need feed suitable for their age and breed, and you should provide this in their chicken house to give them a balanced diet. They also need insoluble grit, such as hard flint grit, to help them digest their food. Oyster shell is a soluble grit that can provide extra calcium in their diet.
Chickens also need constant access to clean, fresh water in their chicken house. In winter, make sure you remove ice from their water and don't use chemicals to do this. Using drinkers should stop young chicks climbing in and drowning.
Don't forget to clean their food dispensers and drinkers regularly. If you change the drinkers, be sure to give your chickens the same type that they're familiar with.
Find out more about keeping chickens as pets.