Do you research for your books especially food animals can and can not eat?
Yes, I have done some of that. As the owner of a soft-coated Wheaten Terrier with a sensitive stomach there were lots of things she couldn't eat. We lost her, at age 14 yr, back in the winter. So, she had a good life. She could only eat dry food, unless it was canned for sensitive stomachs. Rich foods, greasy foods, fatty foods, things dogs like, made her toss her cookies every time.
There is a different kind of food regimen for professional K-9s (dogs) who expend great amounts of energy and must have good strong bones. I spent some time talking with a dog food manufacturer 's representative while researching about diet for these dogs. The specialty foods for very active K-9s include dense protein with balanced ingredients so that the dogs digest a higher percentage of nutrients and expel less waste. Fewer fillers than in regular dog food. That way the dogs also eat less. I had never thought about the fact that a kennel with lots of dogs would think of doggy poo in terms of how many pounds were week get shoveled. And how those shovel fulls represent undigested matter.
When professional K-9s are feed is important as well. Dogs have a hammock-like stomach that swings. When full, running and jumping can cause the stomach to flip. That can result in death if the dog isn't taken immediately to a vet for surgery. So, police dogs get feed after their shift and again at least five hrs before their next duty. FBI are fed by handler's hand only so they earn their calories in rewards all day long. Other professional handlers use a mix of the above feeding programs.
Hope that answers your question. Thanks for asking, Samantha.