I have on the past added small quantities of animal remains birds, frogs, fish from my pond and a mummified cat I found whilst renovating an old pool. The feather, hair and meat elements break down readily but the bones tend to be problematic; maybe a grinder of sorts would do the trick.
Having read the full article and knowing that there is a saw mill nearby I am still a little dubious about collecting the carcasses for my bin.
Composting Road killed Deer
by Elisabeth Kolb
Researchers in New York State are studying an alternative method for disposing of animals killed in roadway collisions.