I suppose my girl is a bit different. She was an abused rescue, victim of a divorce. Wife kept her to spite the ex husband. She kept her in a small aquarium with no heat and no food for almost 2 years. Near death and huge local infection in her face and eyes. My friend rescued her, took her to the vet, and nursed her back to health the best he could but he couldn't really afford it. Now I have had her for about a year, she has gone from just under 8' to almost 10' now and has packed on nearly 14lbs! She is anabsolute sweet heart and will eat any rodent I put in front of her.
As for breeding rabbits, i have never seen anyone breed them in a rack system. It would have to be a pretty big rack. I have raised pet rabbits in the past and they can be pretty picky and specific about cage size and nest box size. If they don't like something about the conditions, they will eat the babies. I don't do it anymore because I am very allergic to rabbits. I stick to raising rats now, I buy burm food elsewhere!
I have no first hand experience with feeding rats or rabbits dog food. I have been told by a reptile breeder/keeper (Rons Reptiles) that some of the fats, proteins and preservatives that dog food provide can be harmful to reptiles. I do have first hand experience of rescuing a ferret that was on dog and cat food. He had many glandular problems through the years that we had him. Most specifically thyroid problems. We were told by the vets that it was most likely due to the dog and cat food, and there is a reason they make specific rodent foods even specific to each rodent!