Snakes can certainly eat baby chickens, quail, etc. Retics can eat whole adult chickens, I have a friend who sells eggs and who raises free-range chickens for human consumption and I get her adult culls as snake food.

I wouldn't put your snake solely on a diet of chicks to prevent him from getting stuck on them.

Also if you can find rabbit kits or fuzzies you should start offering those when your snake is big enough to take them. While it's rare some retics get stuck on rats and would rather eat 4-5 jumbo rats than one big rabbit.