> It is useless to try to time a whelping from when a mating occurred. Semen can live in the bitch for up to 7 days. Eggs take 2 days to be ripe after ovulation and then remain fertilisable for 48 hours. Unless you use progesterone testing or cytology, you have a massively wide whelping window. You could have bred her just before her eggs died and she went over - or you could have bred her way early, 7 days before her eggs were fertilisable (since some bitches will stand throughout).
Sometimes I wonder how anybody managed to mate and whelp their bitches way back before all this 'testing' was available, let alone done. Yes I hear you - and for sure semen can live for some days post mating but at least counting from the first (or last!!) mating is a guide, not to be thrown aside completely. And indeed, not mating more than twice, with a day between, is what I always did so the window
wasn't too wide.
I'd suggest that maybe doing all this testing might be a good idea for the novice breeder, but once you've built up experience, and know your bitches (and actually, their breed) and when to call in the help of a vet, and when to wait, it is just a matter of waiting and keeping a close eye on what's going on - with each bitch and each pregnancy as no two are exactly the same.
Going by a lot of what I'm reading here, your vets must welcome you all with open arms re this kind of testing - and that includes scanning.
"I think, if you don't see pups very soon, then you will need to take her to the vet for an ultrasound and to check puppy heart rates to be sure none of them are in distress. "
I agree although at this stage, I'd go for x-ray so you have a far more accurate result, re numbers and size.