Sorry but they are no problem. I first bred them in 75(first captive breeding I believe) and off and on including the last two years. All without EVER treating one single individual.
The main concern with Greenrat snakes is, THEY DO NOT TOLERATE hibernation(The common stupid captive type). They are a very cold loving species and are active in the coldest months and feed thruout the winter. No, they do not feed like most snakes in the summer, but they "SEEM" to require four or five feedings during a normal winter. We let the cage get as cold as any, but always allow a hot spot for the CHOICE of the individual snake.
Again, this is a good case for folks trying to fix what is not broken and replace it with something that is broken.
You just something fun to think about, a greenrat being a RATSNAKE, I have to wonder why it only occurs in places with warm winters. Kinda odd, as many common ratsnakes(and boy are greenrats common) can really tolerate cold winters. A funny thought, they love cold, but do not occur where it gets cold. Hmmmmmmmmm I must dwell on that. Oh wait, maybe you folks must dwell on that. It appears I already have.
If you wish, I can post any number of greenrat pics(in the field) Cheers
p.s. the main problem is, most collectors without intimate knowledge of greenrats, often commonly find subordinate males, you know skinny, small, full of all manner of pathogens. And think they are normal. Which by the way is the most common accidental find.