I don't 'feed' them corn, but I have been giving them some cracked corn. to help them stay warmer. Today I got the bright idea to save $.60 and get whole shell, since the chickens act like it's manna when they see it!! After I remembered that ducks are supposed to have seeds? So is shell corn okay or not? Just to be clear, this is an 'additive' to their regular diet, just to give them something that creates more heat.