Darby finally came out of his hide

[Bogertophis]

Agree with Sauzo, it's not obvious in the photo but he shouldn't be that skinny. But weaned rats still take a good 10 days to digest, it's pointless
to feed to quickly, as a snake will throw up a new meal if still digesting the first one. The larger the prey, the longer digestion takes.

If he fails to gain weight, get a stool sample to the vet to check for worms. That can cause a snake to be hungry yet stay skinny, because they're
sharing their meals with intestinal parasites, and if they're really heavily infested, a snake may digest MUCH faster than they otherwise can...just
something to watch for.

If you want to feed him weekly, you need to feed much smaller prey that he can actually digest that fast, but probably best to just be patient & feed
every 10 days. It takes a long time for young snakes to fill out, because although they ARE growing slowly, they put on a bit of length that you won't
notice, which makes them continue to appear to be thin.

Hopefully the reason he's thin is just because his previous owner failed to feed him enough. Some pet stores are notorious for that, wanting to keep
snakes "smaller & cuter, & not out-growing their small store cage".

No rush & don't stress him to do this, but a full-body photo might help us here: assuming he doesn't take a deep breath, as many snakes do, just to
fake us out.