In terms of supplemental protein sources for chickens, I have a pretty good perspective on it. May not be the most politically correct, but it is what it is.
I trap the vermin around my flock in the wintertime, and skin them and sell their fur. It is quite surprising to see just what a chicken will eat. A flock of twenty five can turn a coyote carcass into a skeleton in a weeks time, if it doesn't freeze too hard. Even frozen meat is not completely safe from a chicken beak. They will dig through the snow to get to the carcass pile. They will ignore grain and chicken feed and make a mad dash through the snow to get there, so it must be pretty good. The smartest hens hang out near the fleshing beam where I scrape the fat off of the hides. It seems that fat is a hotter commodity than the protein in the winter. I don't do it when it gets warm, too smelly, plus the fur is worthless in warm weather. Quite ironic to see hens feeding on foxes and coons that would have gladly reversed roles.
great recycling!! nothing wasted.

