I am so sorry to hear this. I had the SAME thing happen to me with a litter of Std. Poodles last year.
For whatever reason, 3 of the 9 were born without tail or just a little nub of one. First, a normal looking male died in less than 24-hours, was a constant crier from the time he was born until he died. I suspected that he had something wrong right from the start but everything about him looked normal.
Then I noticed the vaginal opening of the one female without a tail was very, very red about 4 or 5 days later. I picked her up to clean it and put Vaseline on it, thinking it was just irritation. It was irritated alright, her poo was coming out of her vaginal opening! I took her to the vet right away and we discovered there was a 'pucker' like she had an opening to her anus, but there wasn't. So, I had her put to sleep.
Then, that wasn't the end. I had a little girl (had a tail) but when she started walking was wobbly, like she just couldn't quite 'get it'. I took her to get checked and was referred to a dog chiropractor. She looked at the x-ray and found extra vertebrae over her hip area that was causing the problems walking. We started doing adjustments and therapy, but things got worse with the walking and then there started incontinence problems. We had her put to sleep as well.
All seemed fine with the others, found them homes and everyone was happy. At Christmastime, I sent an e-mail to all the people who took the rest of the pups and all are happy except one of the mails who had no tail at all, who has had incontinence issues that started out shortly after leaving here and progressively got worse. The owners never contacted me about it since they love the dog, but it is sad to hear about their struggles with him.
I will NOT breed those two again, in fact, the daddy was neutered while the momma was still pregnant because I wasn't planning on breeding him at all due to an overbite issue. That was my first time breeding and it was heartbreaking to go through and see the problems the little ones had. I am hoping that it was the dad that was carrying the junk genes and not my momma because I do want to stud her out when I am ready for another litter.
So, hugs too you for what you have gone through. Remember, it isn't as amazing that you see problems with birthing, what is amazing is that we don't see more problems in birthing, and that goes for all creatures.