I have a great (cheap) source for a feed base for my chickens. It's basically a ground corn and soybean mix. I add to that oyster shells, and sometimes grit. The chickens do OK on that but don't quite lay as well as when I buy a mix from the feed store. I'm guessing that I'm missing some important vitamins and minerals, and they are not getting it from our soil even though they free range. I'm sure this has been asked before, but can anyone give me some ideas about adding to my feed base. It would be nice If I could find some sort of mineral mix to add to my base. Thanks!