Tasha is a female, about 9 months old, and has come back to the store 4 times now. The first was at about 3m/o, and the reason was, she wasn't getting along with their current pig. The second, a few weeks later, was because their landlord didn't allow pets. Now with this one, she had been purchased/returned with an intact boar (yes, yes, boo hiss, but they bought two cages, so we couldn't refuse the sale), and may have been housed together, so she was put on maternity watch for three months (no pups).
The third, I took her home to foster (or potentially keep). Despite trying every trick in the book (other than a group bath), encounters would end in blood. At first I thought it was my residents (2yrs and 5yrs), but I later observed Tasha to be the aggravator. It was like she just couldn't stop herself. She'd be fine—she wanted to be with them, to the point of even scaling a 12 inch high playpen—then something would click and she'd start challenging, and even taking flying lunges, and at least one full on tussle. When the time I needed to foster her ended, she just couldn't stay. She's full of character and sweet with humans, and I love her, but we've no room for a permanent second cage. So she went back to the store.
The fourth return was just yesterday. It'd been about a month since I brought her back. They fit my criteria for adopting her—experienced guinea pig owners with no children (she can be nibbly when she doesn't want to be held). They had 2 neutered males and one female. They returned her the next day due to aggression towards all three, but mainly the female.
I am completely at a loss for what to do with her. All the threads I've read were for sows with ovarian cysts (which she's well below the average age, but I won't rule out entirely) or boars. Should she be the rare exception to the herd rule and be an only pig? Should we just keep trying until some pig works?
Advice is much appreciated. Tasha is so sweet with people and I really want her to go to a great home.