I would not sell them or even advertise them. I would give them away quietly to people who post local WTB ads for pet-only homes, with a contract disclosing that the snake has a physical deformity that makes it unsuitable for breeding.

The contract would also contain the following as stipulated damages:
- the new owner will owe you $X if he does use it for breeding, and
- the new owner will owe you $X if the critter is sold without being offered back to you first (aka first right of refusal clause).

I would set $X at the market value of the snake plus $50-100 to discourage flippers and/or people who are willing to roll the dice breeding imperfect snakes with expensive genes. I would also keep the transactions local to make a small claims action easy on myself should the next owner breach the contract.

Unfortunately spaying/neutering is not a viable option for snakes or these decisions would be easier.