I began answering this in the other thread, discovered I might have a mutiny if I didn't go buy food for the wee beasties' dinner tonight
and had to delay my response.
The short answer to "inbreeding - good or bad?" is - it can be both. But those are the same risks as with any other form of breeding.
There are 4 types of breeding - inbreeding, line-breeding, outcrossing. Each are tools (or can be tools) within a breeding program and there are/ can be times and places for each of them. The 4th type is outbreeding and rarely has a place in any true breeding program.
Inbreeding is the breeding of two closely related relatives; father to daughter, mother to son, brother to sister, half-brother to half-sister. What a responsible breeder using this as a tool in their breeding program would be hoping to do is to "set" a trait - such as a correct front and double up on positive points about a dog. The down side is one is also doubling up on negative traits as well.
Line-breeding is the breeding of a slightly removed relative - say a grandsire to a granddaughter, a nephew to an aunt, or dogs with many common relatives in their background. This method can reinforce positive characteristics, can be useful in eliminating health problems and one gets a consistency in uniform quality.
Outcrossing is when one breeds two dogs of different linebred backgrounds. This can introduce new desirable traits and characteristics; the down side is that you can also introduce negatives one didn't have before as well. First generation offspring often lacks consistency across the board.
Outbreeding is more the random breeding of two unrelated dogs. Common scenario for this is one neighbor breeds her dog to another neighbor's pet shop bought puppy. They're the same breed but that's about it.
All breeders of any species - horses, cats, mice, cattle, goats, etc. employ these tools in their programs.
Some websites to dig a little deeper:
http://showcase.netins.net/web/royal...ing-types.html
http://carawatha.tripod.com/inbreeding.htm
http://www.rhiannon-cavaliers.com/linebreeding.htm
http://www.thedogscene.co.uk/article...nebreeding.htm
http://www.myotonicmeatgoats.com/Linebreeding.htm
Ton of stuff out there.
Have I been involved in such a close breeding? Yes, and we got a very nice litter - a couple of outstanding Cardigans which gained their championships and some performance titles in the litter as well, some fluffies (which we were aware could happen knowing the background of the parents), but happily no overbites, which was another thing we knew could potentially occur from this breeding. The puppies are now all around 7 years of age, still healthy, happy and being the love of their owners' lives.
Would *I* consider buying a puppy from an in-bred breeding such as Corgimom has described? Yes, I would - but in my case I might be looking at the breeding from a different perspective than a lot of other puppy buyers here might. My perspective would be one of a conformation and performance niche in addition to being my pal. The majority of the forums members here likely would have those roles reversed - family companion and pet first and then maybe other activities.
What would be more of a concern to me with this particular breeding is the breeder. That there isn't a contract is a bother. Are the puppies being sold on limited registration and will need to be spayed or neutered? That the dam has had her health testing is good, not so good about the sire of the litter.
Your friend could ask why she decided to do this particular breeding. Ask why the sire was not tested for hips and eyes. She can even ask about a contract. Send her the link from Emrys Corgis that is in the other thread about what to look for in a breeder. IF the breeder isn't going to "interview" your friend, then let your friend use that website to interview the breeder - perfectly acceptable. I know I'm delighted when questions come up that I may not thought about asking or on things I'd forgotten to explain. Shows someone has done their homework.
Hope this helps!
Debbie