at the moment there alot of bitches that not coming into season or missing.
when my girls go to be mated i always put them on a course of antibotics for the first 8 day of the season,to cover any low grade infection,one vet told me that if you swap a bitch you may start up and infection that may be laying doarment,
when wispa had 3 litter one miss,
brie had 1 litter and on a course antibotics due to be mate next week.
gollie was on a course and she in whelp.
plus when my rush went to stud all the girl that came to hi where put on antibotics and all took by one who didnt go on a course but 6 month later did and she had a litter,
plus on day one i worm the girl and other other drug or treatment before the pup are born why pump them with wormer,flea control and injection it going to have some side effects if not on the bitch it may come out on the bitch.
human and dogs can have ecoil that laid doarment,untill the baby pass the birth cannal and the afterbith and that cause infection and dead, in babys and pups.