Using a leash or harness on a bunny 
is a highly debated subject amongst 
long-time bunny owners and experts 
for good reason.  There have been 
many accidental deaths as a result. 
You see, because rabbits are prey 
animals, they feel very confined and 
trapped when on a leash. If they 
become scared—which is very easy 
with all the new sounds and sights 
outside—they can easily break their 
necks, their backs or be frightened 
to death. 
You never know when a dog might 
walk around the corner, scaring your 
rabbit and causing her to bolt.
Leashes that go around the neck 
are particularly dangerous as they 
can suffocate your bunny if she 
pulls too hard :-(
You'll also want to consider the other 
dangers of taking your bunny for a walk 
... bunnies can contract diseases from 
other animals, and you never know 
what they're going to sniff or get into 
when they're outside. You also have to 
be careful of pesticides, which can kill 
your bunny :-(
If you DO decide to use a leash or a 
harness, you should remember that walking 
a bunny is nothing like walking a dog. 
Bunnies generally don't like to be 
followed, so being behind her when you 
walk might make her nervous. If she gets 
too scared, be sure to take her inside 
right away.
  
 http://www.rabbitsecrets.com/AltA.htm