All bitches are put to a single stud regardless of relationship mate .Cousin to cousin would only occur very infrequently when a new stud is used and would be for her second litter if required .I only use a dog when he's had 5 good seasons on him and a new one would overlap the end of the old stud so I know he's right and still time to change .I had all this documented in my old thread but deleted it.A recent tragedy with my main stud has forced me to use an outcross ,the resulting one pup a bitch ,will be the future from now for me put back to her sire if he makes it 4 more years .