I never breed my girls before day 15... at the earliest. And I've had some stand up until 20-21 days. I don't usually breed them real late.. usually days 15-17-19 works well for them.... but I had a rough blue bitch several years back (Angie - the girl that EVERY dog I currently own goes back to) would breed really late.. I also had a smooth male once, excellent stud dog. He is retired now, but again, he wouldn't even care about the girls in season until they were REALLY ready to breed... never went off his food, never lost weight when girls were in season.. nothing.. he paid no attention to them, unless they were really ready!! (and he still NEVER went off his food LOL) He was a great stud dog, could get a bitch bred really quickly as well... Good luck with your litter! Hope she gives you a decent sized litter this time!