Chinchilla pooping irregularly.

Hi, it's my first time posting and I don't think this is an emergency, but I would like to hear if anyone has anything to say about this to tell me what' going on. Just as preface I have an 8 month old male chinchilla, he's never been very active always super laid back and sleeping, not lethargic just very chill in his cage. When I take him out for play time every day he has a great time running around and playing with all his toys, when he's in his cage though he just isn't active and he occasionally uses his wheel. He always likes to cuddle with his stuffed toy chinchilla and at night likes to come sleep close to where he can see me. When I adopted him two months ago he was on a bad food full of treats and I've been weaning him onto Mazuri, he gets fresh hay everyday too. He's never eaten much and weighs about 450 grams consistently. Lately though his poop has been weird. He occasionally has softer stool, and sometimes its very small or it will come out in clumps. I'm not sure whats causing this and I wanted to know if anyone would have answers or anything I could try to help him. He doesn't like being held much and I don't want to stress him out by taking him to the vet.