Just wanted to update y'all: Last Monday, the previous owner took him to the vet and he weighed 3.2 lbs (on their scale). I took him to my vet this morning and he is now 4.4lbs
Still needs to gain some more but he's gaining and the vet said not to worry- he either wasn't being given enough food before or had some sort of failure to thrive because he was left alone too much. They did a complete blood panel and all looks normal
I'm so relieved. He already feels less boney.
Thanks again for all your input and advice! I ended up using the natural balance rolls and some cottage cheese mixed in with his other food and he's loving it
