Probably not the best but it has worked well for me. A four pound bag spread over a couple of weeks usually does the trick. A couple of my hens had bare skin all spring. Before the blazing summer heat hit them I had to do something two or three days after the extra protein they started getting pin feathers. I'm not recommending this for anyone it's just something you can do when you have no access to another solution.Animal protein would be better.
Don't think dog food is the best protein supplement during molt, especially not that much, pet foods are usually high in fat and salt, not really good for chickens.