By the sounds of things they are wild caught, which would explain the underfed condition. Animals in the wild tend to be thinner because they have to go out and find food instead of having it placed right in front of them on a regular basis. Also caudos are prone to respiratory problems when exposed to high humidity, that's why they are best kept in really dry conditions with little to no water at all. Hopefully they come good once you've fed them up Oshkii, give them a few weeks and they should put on some size. Give them plenty of insects and throw in a few pinkies here and there. Keep us updated on them ??????