Aww, the wonderful concepts of evolution
Well, I never thought this group would be nipping at the heels of darwins theories of evolution. Randy, as you probably know, you just gave a wonderful explanation of darwins 4th theory, of natural selection. Basically, a species survives, and evolves by adapting to its surroundings. This happens by exactly what you said. An animal with unfavorable traits will more likely die before it can reproduce successfully. Whereas, the frogs with the more desirable traits will survive, to pass on their bloodline and genes. It is also known as adaptation. In addition to your last few lines, I agree totally. The more you inbreed, the more likely recessive genes will show up, since brothers and sisters will more than likely have the same recessive genes. When you put two and two together, it ads up, you know. So, as for inbreeding frogs goes, If you don't have to inbreed them, don't. If you don't have any other way, then it isn't going to hurt them the first few generations. I have read that they can go up to 10 generations without seeing adverse effects. If you want to get into genetics and all, let me know. I am definitely no expert, but I have a book that explains it well.
As for inbreeding in the wild, I know it does happen, but I don't think it happens nearly as often as we might think. This goes back to the same thing as above. If a population of frogs has very few "new" members coming in, and if they are all breeding with the same frogs, generation after generation, this species will most likely develop the horrific traits of inbreeding, and will be unable to survive. If you have too much genetic drift (look it up), the less chance of adaptation for that population. And, since environments are constantly changing, a species will die if it is unable to adapt to the changing environment. Anyway, I might discuss this further later, I just can't think too well right now. I am running on low sleep, and too many mountain dew livewires.
So here is my opinion. Only inbreed if necessary. Sometimes it can bring out desirable traits, however, more often than not, it will bring out more undesirable traits. I feel that it will take more than 1 generation or so to cause defects. I would say atleast 6 generations would be safe. Well, thanks for reading this. sorry for any confusion, like i say, I am rather un alert.