Polly want a cracker? Unfortunately, it'll make Polly poop all over your house the minute you let her out of her cage! If you love your little bird and want to let it fly free all over your house from time-to-time, then I've got a patent that should serve as a happy compromise for you both.
There are very broad U.S. government definitions of "meat by-products." They can include, and often do, any portion of any mammal including eyes, bones, head, digestive systems, and even a certain proportion of feathers and hairs.
At the National Funeral Directors Association convention in Las Vegas in October, funeral service practitioners got a firsthand look at a new product that some people thought they'd never see: a pet removal cot.