When I was younger my uncle had chickens and in the winter they feed them whole corn with no problems. While I feed mine cracked corn, it certainly would not kill them to eat whole corn.
As for choking hazards chickens basically have separate "tubes" for eating and breathing so they are not prone to choking like we are.
As for choking hazards chickens basically have separate "tubes" for eating and breathing so they are not prone to choking like we are.