I've been giving my chicken cracked corn for a treat. I've also read a lot that states not to give it to them during warm heated days, that it's best to give it in the fall/winter months. So I take it the same goes for scratch since a lot of prepackaged contains corn. Do I mix my own scratch for them minus the corn? Is there a specific brand (recommend) I can pick up at a feed/supply store? They free range every evening and receive safe, nutritious, protein rich treats every other day. Any suggestions are welcome.