My family had 5 girls, with two that were fairly dominant. This year we lost 3 of them, and I really wanted to have a new piggie. We got a pet store piggie and separated her, but she got through into the main cage. I thought I would let her have a try with the older pigs (4 yrs old) for today, but one keeps picking on her. She's really tiny. I'm not sure how old. We have a really large cage, so there is a lot of room. How long should I keep them separate? Will the older pigs ever accept the new one?