My guinea pig refuses to eat hay and constantly is chewing on his cage
My piggy Gus has eaten the same hay brand his whole life, but recently he’s had zero interest in it, and refuses to eat any. I haven’t changed anything in his diet, cage, or lifestyle. He has 24/7 access to fresh hay, food, water, veggies regularly, vitamin C supplements, and the occasional fruit treat. I’ve checked his teeth, and they look perfectly normal and not too long, so I’m totally at a loss here. I’ve tried to encourage him to eat his hay by spraying it with a flavored vitamin C spray, but he still refuses. I haven’t seen him eat hay in 3 weeks. I’ve been giving him hay treats to try and supplement it as much as I can back into his diet, but I’m not sure what to do. He has been constantly chewing on the bars of his cage, Gus is free roam and potty trained, so he has almost 24/7 access to my entire room including his play area, but insists on remaining in his cage and chewing on the bars. He previously would chew on his cage to let me know he wanted to come out. When I am vacuuming or my dog is in my room, his cage was shut, just to avoid anything from spooking him or potentially harming him. His teeth do not appear to be too long or impacting his ability to chew, so I don’t know what’s causing it.
I’m thinking it is stress from being an only piggy. I rescued Gus from an exotic animal shelter when he was about 1. I fully intended on bringing home 2 pigs, I had everything set up to accommodate 2. But, when I mentioned I was looking at Gus to the workers at the shelter, I was informed that he was surrendered because he killed the last pig he was housed with. The shelter attempted to house him with a neutered female, whom he still attacked. She had to be removed from the cage since he would attack her any chance he got. Gus would lunge at the other pigs housed nearby through the bars on his cage until they ultimately had to move him to a completely separate room. He isn’t a violent little guy with me, and he has never bit me, but he does not like being pet and refuses to be picked up so I don’t force him. He enjoys being around me, climbing on me, and following me, but doesn’t like being touched. I know they are social animals, but I don’t know what to do, can anyone offer any advice or suggestions?
M 3yo Abyssinian Guinea pig
Not spayed
No obvious signs of pain or discomfort
Last vet visit 6 months ago, he is completely up to date and no signs of any illnesses or health issues
He’s a healthy weight and size for his age and has not had food avoidance issues in the past
I am not aware of what his previous home life was like, but I was told previous owner had a very hard time surrendering him