hi,
if both ur bunnys are female then the one pulling out the fur could possable be having a "phantom" pregnancy- mimicing all the signs without being pregnant, when a doe becomes sexually mature and is with another rabbit she will attempt to "mate" the rabbit she is with they can also become aggressive.
it's also a big no no to keep rabbits together as both males and females are territorial and tend to fight, they are best kept on their own.i've breed and shown rabbits for over 10 yrs and had around 70 at one stage all in their own cages. it would be best to get another hutch for the new rabbit they will be much happier then

krystal