To the defense of Carol of the Tuscon Ferret Friends - she just wrote
something she learned from the rodent people. Yes, the rodent community
will use this method because it is what is used in labs (CO2). Below I
describe more about that process, but it is not safe, at all, for
ferrets. This is why they are not killed in labs in this manner. It is
not feasible to do ferrets in this manner. The lab I worked at did not
euthanize anything bigger than a mouse with CO2 because they cited
studies of it being extremely inhumane.

The honest truth for anyone who has worked in a lab is that CO2 is not
humane, in any way shape or form, to mice. But it is still used because
it is cheap. Co2 is suffocation. They labor to breathe. They are still
conscious for many seconds even in the best conditions, looking at each
other, hugging each other, comforting each other, trying to find out
what is going on, how to escape. They know they are dying, and want
air.

To everyone here who spoke up about euthanizing animals, please read
this paper:

http://www.avma.org/issues/animal_welfare/euthanasia.pdf

And please take my words seriously - I have worked at the vet, I've put
down my share of animals, and I've also put down my fair share of lab
mice using CO2.

Also, before I continue, even with how cheap laboratories are in
disposing of animals, no lab I ever heard of used gas to put down a
ferret. Ferrets are not able to be humanely put down with carbon
dioxide.

Mice are much smaller than ferrets. If the labs won't put down ferrets
with their professional machines, which use perfect CO2, there is no
way a home made gassing is going to create enough gas for a ferret to
die painlessly. Mice need to inhale the CO2 for over three minutes to
ensure they are dead. Mice can inhale CO2 and look dead, and live on to
wake up half an hour later. Imagine how this would work with a ferret.
Not good. It takes a tiny mouse, in a prefilled container, over 30
seconds to go semi-unconscious. During this time they know they are
dying. Imagine a ferret going through this.

Gunshots are the way to go if you are seriously considering euthanizing
pets. Ferrets are notoriously hard to euthanize using inhalation
methods (carbon monoxide, CO2) and DO have distress with these methods.
They will not just "fall asleep".

This paper goes into studies done on animals using tailpipe exhaust.
Carbon monoxide, carbon dioxide - both suck as far as putting animals
to sleep. There are reasons vets do not use these "cheap" methods. Do
not try them at home. Gunshot or very hard blow to the head - better,
more humane. But only if you can do it right. CO gives you a headache,
makes you dizzy, and weak. It does the same to animals. Just because
you can't hear them saying they don't feel good while being put down
doesn't mean they aren't having the same effects a person would have.
It is not a good way to go.

The problem with carbon monoxide is that animals do get agitated and
feel distress with it. The problem with CO2 is that if you have a rapid
rise in CO2 levels, animals feel terrible, and have extreme, major
distress (jumping to escape, etc). This is also true if you have oxygen
mixed in (it is somewhat impossible to prefill a container with pure
CO2, since you have to put the animal in the container at some point).
A deep container can be prefilled with CO2 which will settle at the
bottom. Then an animal can be placed inside, the cover put on and
CO2 slowly filled back into the container. However, the animal is
suffocating. They feel it. Prefilling the container is only making it
so they can't get any oxygen easily. This make them suffocate much
faster, but it still is suffocating. The more oxygen, the longer it
takes to suffocate.

CO2 is like putting a pillow over an animals face. Do you think that
is a good way to go? I wouldn't. I watched the mice die in the lab
as I put them to sleep in CO2 containers. Why did I do it? Because the
distress they were in was less as I did it the "right" way, vs. my
coworkers horrible methods (not precharging the container, making the
mice jump and suffer horribly vs the lesser pain when I did it).

And no mammal, no matter what, should ever be put in a freezer. Period.
This is for fish, reptiles, and amphibians. NO mammals. Freezing to
death is not painless, you don't "go numb". You suffer before you "go
numb" for a long time. This is abuse, and no one should ever really
thing freezing a mammal is a good idea. It is a terrible one. The pain
involved with freezing to death is intense and nothing should ever
suffer that.

[Posted in FML 6336]