I just adopted 2 boys from a rescue. I've posted on them before but this is a newer issue. One of the boys is quite big - a little too fat but I'm hoping to combat that with a better diet. But the other boy is really skinny. He's not drastically underweight, but I can feel his spine when I'm petting him. He seems fairly happy and is settling in well - although he is not fond of being picked up, he loves to sit on my lap and get scritches. He does have some old lung issues, but it doesn't seem to interfere with quality of life. I'm just wondering at this point what would be the best way to put some weight on him?