Our first attempt at starting a colony resulted in disaster because my husband put a rat pup purchased as a feeder that didn’t get eaten in with one of our breeder moms. Needless to say our entire colony died within a few days with the exception of the breeding male.

My current rat colony was started 3 years ago with 4 females and the one lone male survivor from the disaster mentioned above. None of my rats has ever had respiratory issues, mites or mega colon. The occasional casualty has been from old age or birthing complications and I did have to put one female down due to a mammary tumor.

My concern is inbreeding! Obviously after 3 years all my rats are related in one way or another. I have two big males and about 20 females that I rotate around.

Should I bring in new blood? And if so, how long do you quarantine them?

Currently they live in our greenhouse in our backyard. My husband says I should leave well enough alone.