We too have have problems with fertility of our SL(also a well known breeder's line). We tried 3 different roosters and trimmed everyones bottoms-the last rooster(our current) is fine. But I think some lines out there are too inbred and are now starting to show problems with fertility. I spent this season looking for quality lines, of different breeders, to play around with and see if that helps. Hopefully, I 'll be overrun with SL peeps next season.