Thanks for the welcome, bantamfan!
about corn as a source of energy, yes I agree that this is a good idea, I can see why that would help keep them warm. In the winter I'll increase the corn to more like 30% of their feed - thanks for the idea!
I will still give them more protein as well...
I am growing three broilers, about what to feed them: I don't use commercial feed at all. I grow wheat, corn, barley and oats on my field. I mix barley, oats and wheat together and give them that "on demand" whole, and I take that same mix and add 15% corn and then run it thru my neighbour's...