1. She is probably biting you because you smell like the other rabbit. You can consider it as her smelling the presence of a foreign invader in her territory. Bringing a new rabbit into the territory of the existing rabbit can put both rabbits in a stressed/tense state because of territorial disputes. You may observe worse litter habits and more “pre-spay” behaviors. If she is not spayed (which I highly recommend), it does make sense even more that she’d get extremely territorial with a foreign rabbit in her place.
2. It would be impossible to bond them in a week. Her aggressive behavior towards you could be a big indication that upon their first meeting, she can show some aggression, but even with that aside, since the male rabbit is un-neutered, any relationship created between the two is subject to change once he reaches puberty and he starts viewing the relationship through a “hormonal” lens. When he is neutered (under the assumption your girl is spayed?), you can begin the foundation of the bonding process. Both should be fixed for this. You may not have had to go through a full-blown bond if your original pair were sisters who matured amicably, but it is generally a different picture for two rabbits who have no past relationship. You can read more about bonding in the RABBIT INFO section of the websites, as well as the bonding stories in the BONDING section of the forum.

I just re-read after realizing your topic says 3 rabbits. I only seemed to get info on two.

Is the 3rd rabbit another young male? If so, please note that it is very common to mis-sex rabbits and you may indeed have one female and one male young rabbit, which can lead to an unexpected pregnancy. Also note that rabbits pre-hormonal phase tend to get along, but the arrival of hormones can make relationships take a 180 overnight and become aggressive/tense, so my recommendation would be separating all three rabbits (though I know space may be tight).

Agree with everything Wick said.

Also, please stop trying to punish her for being aggressive. First of all, it’s not directed at you, but the other bunny that’s invading her territory. Second of all, rabbits don’t respond to physical punishment. While they do live in groups, they aren’t “pack” animals like dogs so they won’t bow down to the alpha if he whoops their butt enough. All that will do is make her more angry. Rabbits cement their pecking order mostly by humping, not by physically punishing each other. Even if they did, they don’t consider humans as part of their hierarchy so it still wouldn’t do you any good. That goes twice for the head pinning. A dominant rabbit will put their head down to demand grooming from the less dominant rabbit. By pinning her head to the ground, your actually putting her into a dominant position. But again, you shouldn’t physically engage with her like this to reprimand her. Either avoid the situation/walk away, or passively stand your ground and let her see that biting you won’t do anything (you’re going to want to have a glove on for that though).

Yeah, retreating would technically give her what she was trying to achieve, so it’s not the ideal solution, I brought it up as an alternative to physical punishment. If you get bit you will jerk your hand away automatically anyway (giving her what she wanted), so at that point walking away won’t do any more “harm” in that regard, it will however deescalate the situation and give her a chance to calm down. That’s where the glove comes in which will allow you to stand your ground without getting confrontational. I would use a thick, heavy duty gardening glove. Don’t worry about it hurting her teeth, they chew wood for fun after all. 😉

Rabbits will give each other “the butt” to show they’re displeased, so you could try that (turn your back to her and ignore her for a while).

Your reaction and its ability to encourage or dissipate the behavior, I think, depends on the rabbit’s intent for nipping. For example, if a rabbit is nipping for attention and you walk away, this would discourage them from doing it in the future; however, if a rabbit’s intent is to nip you to go away, then walking away would then encourage it, since it’s being effective. How to differentiate “nip meaning” is up to the owner’s judgement of the rabbit’s personality within the context.

Depending on the rabbit and their chosen nip intensity, they could bite through some more heavy-duty gloves, but I couldn’t imagine a rabbit doing so from a “communication nip”. My Wick can’t bite through anything if he tries, while one of my Fable’s “test nips” will permanently damage my dry wall, so it’s up to the rabbit and their desires too.

It’s very common for rabbits to experience “referred aggression” when a new rabbit arrives in the house. Rabbits are so smell-oriented, they get confused by the new rabbit’s smell on you.

Good news is that should calm down with time and neutering of the boys.

For now be sure to wash your hands and arms after handling the new bun and before interacting with your girl. It can also help to change socks in between areas, as she can prob smell them on your feet.

Some people have also had success with putting a stuff or a blanket with the new bun, then giving it to the original bun to sniff/checkout/attack to get their aggression out.

That sounds like good progress, I’m sure she’ll calm down again with time as she adjusts to the other buns in the house as well.