Is inter-breeding a problem in the ferret world, or is line breeding permissible?
I think in-breeding is considered wrong by many across the animal spectrum but I don’t see a problem with it providing it is carried out in a monitored and semi scientific way!
You have to remember that although most don’t like to admit it, even a pedigree dog is an inbreed somewhere along the line.
This is not necessarily a bad thing although out-crossing is now needed to make the gene pool larger to free some breeds of genetic faults.
The reason people inbreed / line breed is to fix positive features such as stamina, strength, intelligence etc that their present stock already possesses.
However you can also fix the negative ones too!
The tighter you inbreed the more likely you will achieve something true to type although you also heighten the likelihood of freaks that may need culling.
Daughter/father matings are classed as line breeding providing the mother is of unrelated stock, which is basically watered down inbreeding that takes longer to achieve what you want.
Brother/ sister matings are classed as inbreeding as their genetic make up is the same.
If you are not completely happy with your ferrets? working ability then my advice is not to breed at all.
If you are happy then you have the base to embark on such a project.