I'm sure this wouldn't happen if you entered a breeding loan with the proper person, but since nothing is a guarentee in life I would like to include another suggestion. Perhaps a section of the contract that deals with the worst case scenerio of having to go to court because of breach a contract. Fees when pursuing legal actions and what not can be quite expensive and should be spelled out that the breacher of contract will be responsible for all costs associated with that breach if legal action is necessary. For example, the snake dies due to improper care and you need to be reinbursed, but the person you loaned it too now isn't your buddy and says take a hike etc.

Just a thought.