Sudden bunny Death syndrome?

Question
I've been browsing the internet in search of a cause for our seemingly habitual issue of losing young rabbits to some unknown spontaneous illness. A little background, my children wanted pet rabbits and I wanted to try my hand at casual breeding, as I'd always wanted to rear some litters in my youth. Our rabbits have a large outdoor free pen and our numbers are well managed. The bunnies are very social, friendly and are a joy to have... It seems inevitable that I pick my favorite from a litter and not too long after, I find the infant paralyzed, writhing and dying in my hands. This seems to happen at the age of 6-7 weeks just after the mother has naturally weaned the litter. I check on the rabbits several times per day, handle and play with them. I've observed the older rabbits and they all get along- no roughing each other up. No other animals get into the pen. They all seem happy and healthy until one morning I go out there and theres one in the stages of death. Recently I lost two (littermates), one after the other in less than 24 hours. No sign of diahrea, eating and drinking fine, happy and social.. next day they are laying on their side, posturing with a limp head. We do not have a rabbit vet nearby at all, and there is nothing that could be done at that stage anyway. I hope to find possible causes, so that I can prevent such sudden deaths in the future. Can you offer any insight?

Answer
Dear Torry,

Before you consider breeding the bunnies again, please read this very important, short article:

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

Sadly, the only way to know anything about why these babies are dying is to have a post mortem exam done on them.  The signs you describe--lethargy, sudden limpness and then death--are not specific, and could be caused by just about any illness.  Baby rabbits are extremely susceptible to respiratory infections, and they show just about NO signs at all until they are close to death.  A post mortem exam by a good vet *with* histopathology on major organs (including the lungs) will reveal if this is a chronic problem with your babies.

I would suspect respiratory problems in the absence of any sign of diarrhea.  But the other *very* common problem with baby rabbits is E. coli infection in the intestines.  This can kill within hours if not caught in time--but the signs include severe, very smelly diarrhea (usually greenish).  This can be treated with a protocol I've developed, but since you say there's no diarrhea I won't send it unless you tell me you'd like a copy.

Other things to consider:  are there toxic plants about?  Possible exposure to pesticides?  Fungi?

Unfortunately, without more information, there just may be no way to know for sure.  I am very sorry about the loss of your dear little ones, and hope that this problem will not happen again.

Take care,
Dana