What types of rats should be purchased/heldback to produce the best breeders for our snakes? By best, I mean the healthiest, highest number of babies, longest life, good disposition, etc. I know there can be variences within any particular group (huskies, hooded, etc) but in general if you were starting all over in creating your rat breeding colonies, which would you choose and why?

Do you exclude any as potential breeders because of color or markings? If so, which ones and why?

Thanks