Hey, just needed some advice on a dog a friend and I have semi-adopted.
We had a dog that wandered around our neighbourhood, and he was in pretty good shape, and gradually, we warmed to him and kinda took him in. We got him checked at a vet, who gave him a clean bill of health for a stray. He pretty much lives with my friend, who feeds and waters him, and gets let out to wander about in the day. He always comes back at night without any problems.
From the day we got him, he's always been very friendly and docile. He got a bit territorial at one point, and started to bark and growl at people who tried to come into the house, but generally, as long as we let him get used to the people who were around, he would more or less ignore them and curl up to sleep in a corner.
However, recently he's developed a rather nasty streak. It started one day when he growled really ferociously at a friend who he had previously known and been on civil terms with who just happened to walk into the house. He kinda calmed down after a while, and let our friend alone. However when the same friend came around the next day, he got really vicious, and actually lunged at him and bit him pretty badly on the arm, putting a puncture about two centimeters deep. We put a muzzle on him, and he seems normal most of the time, but occassionally just goes ferocious and growls and lunges at people again.
We've took him to the vet this week to arrange an appointment to get him neutered hoping it would help, and the vet also said that he had a slight infection they discovered while taking a pre-surgery blood test, and we were wondering whether it was the infection that was causing him to get cranky. We've been feeding him anti-biotics, and we're gonna get him neutered regardless of what happens after he finishes his medication.
My question is, what could be the possible causes of him just becoming so unfriendly? He was never vicious at all in the past. Is him being sick all there is to it? Will the neutering help? In all seriousness, if there's no significant change in his behaviour, we're probably going to have to go have him put down. He actually snapped really viciously at my friend's girlfriend today, and would have bit her pretty bad if she hadn't instinctly jerked back, and that's the first time he's ever been hostile to any of the three of us who he sees everyday. He's also recently become a bit more antisocial. He used to sleep in my friend's bedroom with them, and would happily jump into the bed in the mornings and curl up with them, but recently, he's been a bit of a loner at night and gone to sleep on the steps or downstairs by himself. Which would seem to be indicating is his illness that's making him grouchy. But I was just wondering if there's any possible cause we didn't think of, and any other steps we could take because he's really a pretty decent dog, and has been that way until the past week, and it'd be sad if we had to have him put to sleep.