I mated my girl last Saturday and Monday. There was doubt about exact first day of season as I may have missed it - she was a bit earlier than I expected but mating would have been between 13 to 15 days first mate. Good ties.
I have a draminski ovulater and used this as I have before and readings indicated that I was around the right time . But yesterday my neutered boy ( who would have made a brilliant stud dog ) was jumping on her back and she was flirting with him and one of my girls too. She has had a litter before but can't remember if she did this last time, this many days after. Any one else had that happen?

It might be your boy is humping for the sake of it and an experienced stud dog wouldn't bother if she has 'gone over'. Some of my girls hump each other for the length of their season, even my 10 year old does it!

Had a scan to-day and yes she is in whelp. 5 weeks to-day 2nd mating.
I used a lady who has her own scanning machine and it was a very pleasant experience.
Wondered if anyone had any advice on the following though.
She said she was very gassy so it took a little longer to see the puppies ( not ever so long though )
also she said she thought she could see 2 clusters of puppies one cluster looking more developed than the other.
I never got any detail from my vet on any of my scans. Anyone else had this sort of report on a scan?

At time of whelping you can get instances of one or 2 pups being more premature than the rest but provided she doesn't deliver early then they would be viable. Poor placental function/too many pups to nourish can also cause slow growth in some.

According to what we are told a bitch releases all her eggs together and 2 days later they are ripe but I wonder if some bitches vary this and release some eggs later which are then found by the longer lived sperm a couple or more days later.