If your rabbit is good about letting you pick her up it would be no problem having her out unleashed. If she's the type that don't follow you back in the house or refuses to let you catch her you would need to start with a leash. Loose rabbits usually find their way back home specially to the...
Are they big cages. You might try letting them run around in a large area. That way they have space to back down. If they are at each other's throats in a big space. You may have to keep them apart.
Does she bite always when you put your hand in the cage or only when you're late with...