It's easier to find organic quality dog food, than it is to find organic chicken food, plus I can get orgnaic dog food that doesn't have soy or corn in it. Just look around in your area at the types of dog foods, if you are comfortable, and read lables, understand them and them make that decision. I'm comfortable with it, but many are not, since many aren't comfortable with feeding their poultry animal meat...I've been known to feed my chickens butchering remains, but I understand how chickens are. I would never feed my goats any meat products, because they aren't meant to eat it.
Mine are also allowed to range daily, which helps out a lot for their moods and diet. As for eating the eggs, I feel comfortable with it, but again, I'm comfortable with what I feed them more now than before when I was settling with chicken food. No, I don't believe it's standard practice, and most people would do what you did, gasp, omg you're feeding your chickens dogfood?!
I choose to look outside of the box for my animals nutrition, and so I learn about what their needs are and find a source I'm most comfortable with and works for them.Food Grade DE