I kind of equate it to making my own chicken scratch....WinCo here in Boise sells a lot of bulk grains but there are so many different cuts and mixes, I wasn't sure what to get. They have whole dried peas, whole corn, cracked corn, barley, flax rolled oats, whole oats, tons of stuff....can chickens pretty much digest any form of grain? Or am I looking for some specific types?