I understand how separating the feelings for both hobbies can be hard for many people, but I was surprised how easy the change was for me. I felt bad when we fed off our first litter, but quickly got used to the fact that I breed rats for fun and feeders and that either way, the rat was not going to waste.

On one hand, I find that keeping feeder/pet colonies mixed might make it a bit harder to separate the feelings, especially if you are feeding off the babies of your favorite momma. However, I would rather have this than people segregating colonies and clearly giving the pet rats attention, better enclosure care, etc while the feeder colony just gets the bare minimum to produce.

I guess I really have not said anything worthwhile, but basically it comes down to whether or not the rats, both as a species and individual animals, are being cared for and "used" efficiently. If they are used as feeders, they have a good purpose for their death, to sustain another life. If they are used as pets, they bring joy to the keeper. I don't think it is up to anyone but the individual keeper to decide which is right, wrong or better.