Because, according to Shaun Belongie, the national brand manager for cat food company Friskies, the FDA says you can't.
It holds pet food to the same sanitation and safety standards as it does human food, approving ingredients it deems appropriate, and necessary, for an animal's diet.
Rodents aren't sanctioned to be grown as a food source in the United States, and the Department of Agriculture doesn't have an official inspection procedure for mice.
So while fish are a go, mice are a no.
