As a so called purist myself I see nothing wrong with doing your project. That said, if all were to take such a careless approach to purity(not your project but rather your definition of purity) there would eventually be no pure snakes with which to create fantastic(I'm not being sarcastic I really do mean fantastic) hybrids. That said, I refuse to believe that anyone with a modicum of experience at breeding snakes here really doesn't believe there's such a thing as a pure snake... it's just wordplay to say that.
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www.hcu-tx.org/