Good point Mark. I think that I look at my colony a bit like a farmer does. I want a good producing animal, one that breeds and bears young appropriately, is physically healthy and has a sound temperment. Because the rats do come in colors and patterns I might determine I want a specific female of a litter versus one of her female littermates solely on her more pleasing look but as long as it's a genetically sound decision, then I consider that just a side benefit. I grew up with a lot of farmers and most smaller, family farms named their breed stock, cared for them extremely well but still quite happily sat down to eat steak from their offspring or a nice pork chop from "Suzie's" litter.