Quote Originally Posted by MarkS View Post
Any time you bring in new mice, you also risk bringing in the diseases that they may have....(stuff deleted)....I'd much rather risk a little inbreeding depression then lose the whole colony by bringing in new stock with diseases that my colony may no longer have any immunity against.
That's a good point, and I had not thought of it that way. If I were to bring in new stock, I would obviously quarantine. However, that doesn't necessarily protect against something the new stock is carrying but does not show symptoms.

I think another thing is a lot of people misunderstand inbreeding. It does not cause bad genes to spontaneously appear. Random mutations do occur, but that will happen whether or not your are inbreeding. What inbreeding does is increase the chances of a bad gene becoming widespread throughout your colony. If you have a colony that has good genetics, or even if you have some bad genes but have enough good ones and selectively breed for the best animals, you should be able to maintain healthy stock even if it is extremely inbred.

Please note I am speaking hypothetically and based on what I have read & heard from people who do have the experience of inbreeding their mice for many generations. Although I have already done some inbreeding in my mouse colony, I just haven't been at it long enough to be able to speak from experience as far as long term effects.