Rabbits naturally chew everything in sight. Don't offer too many toys at once. Keep some in reserve and change toys regularly. Try setting aside a small, enclosed area without the cage for your rabbit to play in. Make sure there is nothing else but her toys to play with. When she's in the cage and chews it or anything inappropriate, say a firm "no" and offer her a toy. When she accepts the toy and stops chewing the cage, praise her.