Inbreeding is absolutely not nesscessary, especially if you're breeding normals. You also can get interesting animals by breeding interesting animals together, as long as their appearances are not caused by simple recessive genes. Inbreeding only comes in with snakes that have traits due to a single recessive gene. If you have the only albino member of a species, the only way to get more albinos is to breed it to snakes that carry that specific gene- ie, its relatives. That's just the way genetics works. Albino does not show itself if you breed an albino snake to any normal snake.
Also, pattern and color abnormalities can be caused by things like incubation conditions and random chance. That's why a trait has to be proven to be a simple inherited trait in order to be accepted as one.
Also, inbreeding only rarely seems to cause problems in reptiles, although I think that many problems may be pretty subtle and not generally recognized. But this takes many generations. The small amount of inbreeding done to 'fix' a trait is generally ok as long as that line is outcrossed later. I do think inbreeding overdone in some instances and I'm trying to avoid it myself. Lots of people do it out of apparent laziness or greed.
(the most inbred animal in my house is undoubtably my dog, who is a purebred. if i ever get a snake that looks as weird compared to the 'wild type' as my dog i'll KNOW i'm doing something wrong)
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Eryx - All the fun of a boa in a convenient pocket size!