I had a brother /sister pair together this year (nest mates) ...... ( i never tried to pair them they done it themselves ) but in the 1st nest they only filled the 1 egg and the doo looked ok but was late from training quite a few times and the next nest the only y/b in the next never opened it's tail feathers ok (they were piped and it was never right :-/ ) needless to say that pair were parted and wont be together next year i can tell you that much but they are very well bred so we'll cross them and see how we go next year :-/ :-/ :-/ :-/