Skinny? This was a bit bemusing to us. The number one chronic health problem with llamas is them running to fat. We have been reasonably good about giving Herc only his llama chow and hay, and I try to keep his nose out of the goat food, but we haven't been rabid about it. He's had his chances, and plenty of them. But the vet talked about how hard the winter has been, and how Herc probably ended up burning more energy than the llama realized by playing in 2 feet of snow for most of the winter.
Along with keeping a sharp eye on his litter pile for any signs of parasite problems, the vet recommended that we raise his llama-chow ration by about a half or a little bit more. We should keep his feed at the higher level at least through the springtime, until and unless we have full pasture for him again. Also, since llamas have far less parasite resistance, we may want to consider a llama-only pasture for him to graze that doesn't have any goat poop in it at all.