I've been talking at length to a borzoi breeder who seems really great in every way. Experienced with the breed, checks all the boxes in what to look for in a good breeder. However, I just found out that for the upcoming litter— the one I was planning to get a (companion) puppy from— the parents are siblings. Is that a normal thing to do? I asked the breeder about health effects of inbreeding like that, and the breeder said that genetic tests were run before deciding to breed them. Both the parents are national champions, so I guess the breeder wanted to maintain some traits? I am new to this, so I wanted to see if the inbreeding situation is as concerning as it sounds?