What it really boils down to is what do you have invested in the animal itself and how much profit do you want to make.
Lets just say it costs you $500 to keep a pair of your breeders for a year. They breed and have 10 or more babies. Now you get say $100 clear profit from the babies(after expenses of shipping).
Well you just made $500 tax free profit with the enjoyment of keeping animals you love. Now you do that with your collection and you just made some nice pocket change from your hobby.
Dont get me wrong I agree with on teh part with people selling alot of animals and that they are eating more of teh expences then the average buyer. But if you are selling that many animals then you are also producing that many more witch will increase your profit margine anyway.
Just my thought on things