
In reply to your question, I think you need to get something from the vet to worm them again. I would also worm your other dog, don't be in too much of a hurry to let them mix. I suspect by now you have realized what a poor home they have come from and from your post I imagine you will not be taking them back! However you say they are in poor condition and I would be tempted to have a quarentine period to ensure it's not just fleas and lice...make sure they are not carrying any gastric problems before you sibject your dog to the possible infection risk.
As with the good advice you have been given you have taken on a lot. It would be possible to get them clear from bugs etc and maybe think of finding a lovely home for one of them...two pups together is very hard work. That way you would not feel you were putting them back into a risky environment.
I know in the real world it is easy to be wise after the event but do think about rehoming one. They would be better to have some one on one training and would probably bloom into lovely happy dogs that way.
As a warning for anyone reading this, to get a pup from an unreliable source in order to save it from a horrible place is very misguided and like others have said it just perpetuates a market for these vile puppy dealers who have nothing but money on thier adgenda...and they are very capably of spinning a tale to make you feel sorry for the pups!! But remember..If they have NO market, they will stop the breeding...
Aileen