How do you know how much cracked corn is too much? They are so fluffed up for the winter I can't tell if they are getting fat, but we give them a good bit of cracked corn to keep them warm (we don't heat the henhouse and it can be single digits to sub-zero for days).
I think we probably feed 6 hens and 2 roos about a cup of corn a day along with their regular pellets, sunflower seeds, flax, crimped oats and, of course, spaghetti in the morning!