I have only had chickens for about 2 1/2 months now. 8 of them are 2 1/2 months old so they are still on the medicated chick starter/grower. Someone gave me an americauna that is probably a couple years old. I did get her a layer/breeder type feed. I didn't know what the bid difference between pellets and crumbles were as far as what is better, or is it just preference? Right now they are all eating crumbles. Also I didn't know if it is necessary to mix feed for a short time if you were going to switch to a different brand or to pellets? I am an RVT and know a lot about puppies and kittens, not so much about birds haha!!