I’m so so sorry for your loss, I can’t imagine…

I’m really not sure, but the fact that they all occurred in sequence like that makes me think of something infectious. Hopefully some other members will chime in.
Do you have other bunnies still, or did all of them pass away?

Where are you located on the globe (not specifically, but what country)? I ask because I immediately thought of rabbit hemorrhagic disease: http://www.cfsph.iastate.edu/Factsheets/pdfs/rabbit_hemorrhagic_disease.pdf

It was just recently confirmed in Ohio, and there are not currently vaccines for it in the US, but there are vaccines for it in the UK. Have you spoken to a vet about this?

Again, I’m so so sorry

Devastating. I’m so sorry.

Would your husband consider having a necropsy done on the bunny that died today? Maybe that would give an idea of what has taken them all.

Very possible RHVD like Dana suggests. It’s RHVD2 strain that has been confirmed in Ohio. Its been present in other countries longer.

RVHD2 is often fatal, although some rabbits have recovered with veterinary care. What makes it more dangerous in some ways is that it has a longer period in which the rabbit is infectious, this results in the disease spreading more widely. The strain can also be less easy to recognise because there is often no visible bleeding, so rabbits can simply be found dead or ill with no obvious cause. Due to the lack of obvious symptoms, owners often do not realise their rabbit has an infectious disease and this results in:

The rabbit not being given treatment early enough.
Precautions not being taken to contain the infection.

Source:https://rabbitwelfare.co.uk/rabbit-health/rabbit-vhd/
*note, this info is from UK organisation. There is a vaccine available there for all strains now. I’m not sure what treatment is available even if an owner did suspect their rabbit had this. Time is not on their side.

Another possibility would be if feed was contaminated. You’d need to get samples tested to confirm. I would have thought you’d see some symptoms beforehand if that was the case.

Oh.. then that makes me suspect calici even more. We can only vaccinate against the original strain and some variations. We don’t have vaccine for RHDV2 here. That version has been present here for 2-3 years.

If it is calici virus, it can survive on inanimate objects for months.
The AVA recommends: “All cages and equipment should be thoroughly cleaned and disinfected. Disinfectants that can be used to decontaminate any equipment include 10 % bleach, 10 % sodium hydroxide, or parvocide disinfectants. If using disinfectants material safety data sheets must be available and consulted, prior to use. Autoclaving will also kill the virus.” http://www.vetvoice.com.au/ec/diseases/rabbit-calicivirus
I personally would not want to outside hutch at all, even if possible to disinfect it.
If you were to get another rabbits, I definitely get one that’s already been vaccinated but even so, even vaccinated rabbits can become infected. And our vaccine does not give protection against the RHDV2 strain.

I’d contact some local vet clinics that see rabbits and see if they’ve been seeing increase in cases in a specific strain. Dr David Vella is one vet I know of in Sydney who is regarded as a rabbit expert. http://www.exoticsvet.com.au/contact/

I’m so sorry you lost your buns. It does seem to have been rabbit calici virus, one of the viruses released to control the population of wild rabbits in Australia. . The rapid deaths 5 in a row like that are typical. It doesn’t kill 100% of rabbits, The vaccine you have access to in Australia, Cylap, is supposed to protect against both the old and the new strain of calici. No vaccines give 100% protection though.

The virus is very good at surviving in the environment, so everything in the house that your rabbits have been in contact with should be disinfected with for example Virkon, machine-washed at a temp above 50 C, or completely disposed of before you get another rabbit. If you get another rabbit you shouldn’t bring it home until the vaccine has reached its full effect, and that can be 3 weeks.

This is very sad. Where I am (in Europe) there’s just now an outbreak of RVHD2. We have a vaccine but practically every day I read about new deaths from confirmed RVHD2 in unvaccinated rabbits around where I live.

I’m so very sorry. That is absolutely devastating to hear about. My very sincere condolences to your family.

That virus is so horrible.

(((((Binky Free Bunnies)))))

I have had a small string of unknown deaths the past two weeks. Both with rabbits who have other medical issues. My most recent was fine up until one night where he was lethargic and had an inflamed ear. I brought him to the vet wo prescribed bayrtil and gabapentin for an ear infection. A few hours later he was gone. I have always considered myself a good bunny mom but the loss of two rabbits in a week is making me think that I am doing something wrong. Neither of my rabbits had a loss of appetite prior to showing symptoms and with the second the veterinarian was comfortable sending him home right before his death. If anyone as any insight I would really appreciate it. I have another rabbit who has been with me for 1.5 years and if I lost her I would be completely devastated. She seems perfectly fine right now (aside from losing her mate).

This is scary. I could not say what happened to your beautiful buns, but I am pretty sure what happened to my first. Someone built a pen, but used treated lumber. Later on I learned that it is treated with arsenic. Beware of what types of wood you use around your bunnies.