Be very careful adding protein; you can overdo it. Although I normally go all organic, I got my girls a Purina feed called Feather Fixer. It's got 18% protein - more than that isn't recommended. It's supposed to help with regrowing feathers and getting them back to laying. I'll take them off just as soon as this second bag is finished. I mixed it with their organic feed because they didn't like the Feather Fixer. They're used to it, now, though and I think it helped some.
I just got another bag of the feather fixer. I really like it and my girls do too. But it's $18 plus tax here unless I can find it on sale.