High protein doesn't show on the outside, but can cause fatty liver. Great if you are going for foie gras though! Most game bird finisher is around 18%, which is plenty of protein. Your winter feed consumption drops with scratch grains because they provide more energy, not protein. The scratch grains give them the extra energy to stay warm! In a sense, you made your own 18% mix. Scratch grains are quite low in useable protein, so you are essentially diluting your 21% feed down to a healthier protein level. That's why it works so well! Just don't feed them exclusively 21% feed, and they will keep on thriving! You may also want to consider adding a little extra calcium into the mix for your layers.
Oh my gosh thanks! I really needed that information that's very helpful I am glad I know that! Awesome ok that makes sense now! e