I have called my vet and around town. Ivermectin (or Ivermec) is available by prescription only. No-one else carries it but the vets office and they said they'd only sell it to me if my dog had heartworms. For no other reason. I am waiting to hear what other wormer I can use for gapeworms. I am really upset that I cannot just buy a wormer when I need it without a hassle or prescription. It's ridiculous! Just another way for them to make tons of money!
We still aren't sure if it's worth worming them. Sure, it'd save them...for now...but what about re-infestation? The worms can live dormant in the ground. We'd have to move or relocate their pen. I don't see how. It's looking like we might have to kill them all. I am just sick over the whole mess!! Thanks for all the responses!