Any breeding should only be done to benefit the breed on not only looks and temperament, but also genetically. If you don't know about genetics... you should not venture into breeding. There are also a myriad of medical testing that should be done PRIOR to any breeding to make sure that you are breeding a sound specimen and hopefully contributing TO the gene pool, not taking away from it.

Breeding should never be "for fun"... if it is, then you are just a backyard breeder. I hate to be that blunt about it, but breeding should be taken WAY more seriously than "I have an intact male, you have an intact female, let's breed them for puppies!!".

If you really are serious about this, I strongly recommend you look into some local border collie clubs in your area or online and reach out to some breeders there... and perhaps choose one to be your mentor.

Re: pet overpopulation...

You say that pit bulls are the problem when in the same breath saying that "other mixes like aussies, BCs, goldens, etc, were adopted out much more quickly". Well... of course they were... for every aussie, BC, golden, etc that was adopted out means that a pit bull puppy was passed up. ANY puppy bred, intentionally, unintentionally, responsibly or irresponsibly, is adding to the pet overpopulation... it does not matter what breed it is. If you're going to do it, at least be responsible about it and do it right or don't do it at all.