Hi,
I have a male/female bonded pair that I worked on bonding with my newest neutered male for a few months. I think it could have worked out if I had continued but I decided to stop because the dynamics of the group got so weird and I was very concerned that it might break the bond between the existing pair. That can happen and I didn't want to risk that. To me it would have been totally unfair to have one of the currently happy pair become the "odd bun out" and that can definitely happen.
Bonding a trio is definitely possible. There are some members who have done it very successfully. However, it is my understanding that creating a trio is generally difficult and doesn't work more often than it works. That was the advice I got from our state's HRS people based on their experienes and, based on my experience, I think I agree.
They lived next to each other with an adjoining wall for about 3 months and I would switch sides every few days so they didn't get too territorial over "their" side. Sometimes it was nice and peaceful, but sometimes the male from the existingpair would attack his female partner if she groomed the new guy or sometimes attack her for no apparent reason. Also, the two males sometimes got along well, but out of nowhere they would start to fight. When I worked on bonding them in neutral territory, skirmishes always broke out and it seemed stressful for my female.
I don't feel like I ever would have trusted the two males together 100% because after weeks of peace, a fight could still break out, and, likeI said,I began to feel like it was a pretty stressful situationfor my little female. Her litterbox habits got worse and the boys would mark by pooping and peeing along the adjoining wall a lot. Also, the main thing for me is thatI thought it would be wrong to risk breaking up my pair who'd been together for a year. I decided it would be better to work on bonding my newest male with my single female. I've been working on that for about 3 months now.
Every situation is different. Sometimes it works, sometimes it doesn't. This is just what my experience was. I'm totally envious of the people who have trio's that work out so easily
.
Also, keep in mind that if you get a male his hormones won't die down for several weeks after he is neutered so you wouldn't want to introduce them until you are sure he's "neutralized".