U_Stormcrow
Crossing the Road
I don't have the link anymore (computer crash) but I once read a study where protein in the range of 30% could cause avian gout. To me that is the protein level not to exceed for any chickens. And this is my opinion but I feel that if you get into high ranges of protein you start to have waste.
Similar to this one I assume (34.7%), using chickens as an analog for the study of hyperuricemia in humans.