You may or may not have a harder time selling these pups. Either way, it is your responsibility to inform potential buyers about the hernias, their risks, and costs to repair, so that's good you are looking for info. I agree with Instyle that you really need to have health clearances done on both your weims before you consider breeding them again, and they should be doing something besides just being pets.
As per the umb. hernias, have you checked with your female's parents' owners, as well as the stud's parents' owners, owners of offspring of the stud, siblings
of each dog in each generation of the pedigree, etc to see if any have had umb. hernias? If not, you should, and if any give the same reason that you have (the dam pulling the cord), do not
ignore the incidence- mark it as affected on the pedigree. Hernias can be inherited, so if you check with as many of the dogs related to your dog as possible, you might just see a pattern. (If you don't know what know what kind of pattern to look for, do some research on basic genetics, which is the minimal any person breeding animals show be familiar with.) In my experience, breeders may just say that it was the dam's fault either because they haven't looked into the bloodlines thoroughly or because they are trying to cover up an inherited condition- which is why I wouldn't ignore any hernias in your litter's family that the owner/breeder tells you it was the dam's fault. Also, don't ignore any of them saying that they only had "delayed closures," which is essentially the same thing, just semantics.... Some think it is a such a minor thing that it doesn't need to be bred against, but anything that often requires surgery and poses a health risk to a pup, IMHO, is something that should be bred against.... Sure, it's not as major as hip dysplasia but I personally think it should be considered....
Sometimes, yes, a mom can chew them off too roughly/aggressively damaging the umb. ring, but it's a hard one to prove unless you have a solid understanding of the health conditions that run in your female's bloodlines. I'd hesitate before breeding her again, until you have checked into this, especially because so many of the puppies were affected. Sure, these may not have been due to genetics, but why take the risk, since they can be hazardous to the pups and cost extra money....
Also, keep you eye out for undescended testicles (cryptorchidism); this is a condition often linked to inherited umb. hernias. It could serve as another clue.
Personally, I would discount the cost of the surgery from the pups or keep the pups until they are 12-16 weeks to have the surgery completed yourself. I haven't seen any that closed up on their own when they were the size you mentioned. I second Tess that the surgery cost your vet quoted seems pretty low; I would figure at least $120/pup.
Also, unless you look really
hard and still find that there is no pattern of umb. hernias in your female's and the stud's families, I'd recommend you send these pups to their families with spay/neuter contracts. I wouldn't consider them breeding quality- some don't mind, I do. (Personally, I'd hesitate anyways because of the sheer number affected in your litter.) On second or third thought
, I wouldn't recommend sending these guys home with anything other limited registration and spay/neuter contracts, unless someone on your waiting list has actual, concrete plans to show or otherwise compete (ie field trials).
Lastly, any pups with repaired hernias will not be able to be shown, either, although an unrepaired umb. hernia is typically not cause for disqualification.
Sorry for the info/opinion overload; I don't know what you have or haven't done in prep for this litter.