Behavior Problems in Foster Bunny

Question
I am a foster mom for the local animal shelter.  I have had  good success with previous bunnies, but Dimitri is a challenge.  He came to the shelter a "good bunny", sweet and curious once he got used to the place.  Not long after his arrival, he got a respiratory ailment that was going around, and he had to be confined to his cage for a week.  Since that time, Dimitri has become very cage aggressive and this one behavior has been his undoing for many potential adoptive families.  Dimitri is now on "borrowed time" and the shelter is counting on me to redeem him before they have to make difficult decisions about him.  

I've read previous posts on bunny aggression, but they don't seem to fit Dimitri’s specific problem.  For instance: he grunts and lunges whenever someone or something is near his cage, such as another bunny or an item being placed within a foot or two of his cage.  He will not allow me to fill his bowl with pellets.  Once he's out of his cage, he's fine, though still distrustful of humans.  I am currently allowing him free time outside the cage, allowing him to approach me, and feeding him his favorite foods from my hand.

My questions: am I correct to assume that his aggression was triggered by being medicated?  If so, how do I reverse his thinking?  How can I limit his aggressiveness if an object comes near his cage?  Thank you in advance for your assistance; Dimitri will thank you immensely once he realizes what road his behavior is sending him down!

Answer
Dear Stephanie,

Yes, I think it's very likely that Dimitri became aggressive because of the medication.  It takes a bunny (especially a smart one, as most aggressive bunnies are) a long time to forget things like that.

The best solution, of course, would be to get him into a home situation ASAP where he can live uncaged and learn that humans  can be trusted.  It's extremely difficult to stop a bunny from being cage aggressive if he can never come out of his cage.  You can find some tips for winning the trust of a shy/aggressive bunny here:

www.bio.miami.edu/hare/shybun.html

I personally love the grouchy ones.  Once you win their trust, they become the most loving, loyal companions.  But this doesn't help Dimitri in the short run!  I would strongly urge you to write to the House RAbbit Society behavior expert at behavior@rabbit.org for tips on how to cure Dimitri's cage aggressiveness while still in a shelter situation, if you can't get him into a home to win his trust.  I have more experience with curing aggressive bunnies who are in *pens*.  Cages are a very difficult matter, but I'm sure our HRS expert will be able to help you save Dimitrie's life.

I hope this helps! Please write back if you have any other questions.

Dana