many years ago, i borrowed a hen that had topped a fed, to pair to a cock of mine that had topped the fed,,,, each of us had a yb apiece,,,, my yb off this pair won a race,,, it was then we matched the pedigrees of sire and dam,,,,,, they were in fact brother and sister,,
this was complete fluke in this paring, i probably wouldnt have mated these two, if i had known,, but there you are,,, nowt as strange as pigeons