congratulations on your litter, no stud pants are going to keep him from getting your girl when she is in heat, my stud can get out of a straight jacket if I put him in one,
the only way to make sure is to keep them in separate rooms or kennels my boy stops eating and becomes love sick..
and giving the opportunity they will get to her FAST.. so PLEASE be extra vigilant if you don't want that gir pregnant every season. the best way to prevent this would be to spay and neuter them.
Best of luck,
Carmen in nj