Zombie baby rat

[satomi325]

Death by freezing is one of the most horrifyingly painful ways a warm blooded vertebrate can die. Please don't take that advice.

The bit about gassing them for longer is helpful though. Maybe try a smaller ice chest next time with the same amount of dry ice.

Actually, freezing is one of the listed humane methods to euthanize a pinky according to IACUC (The Institutional Animal Care and Use Committee - they regulate the care and use of laboratory animals in the US).
While it is listed as cruel and painful for all animals, the typical CO2 and cervical dislocation may not be effective on pinks. Rats under 2 weeks of age have a high resistance to hypoxia so they are highly resistant to CO2. And their tail/bones aren't developed enough to pop their necks.

Feeder breeders do however, 'flick' their heads to kill pinks as humane form of euthanasia.

I do agree with you 100% that freezing is painful. But in a case of pinks, it is more humane to freeze them straight out then put them through a gas chamber and have them survive. All rats older than 2 weeks old can be humanely euthanized in the typical fashion of CO2 or cervical dislocation.

Carbon dioxide (CO2) is currently considered to be a safe and humane method of euthanasia that has long been the preferred technique for use with rodents. CO2 should not be used as the sole method of euthanasia in neonatal rodents, because the time required for death to occur may be substantially prolonged due to their inherent resistance to hypoxia and hypothermia. The use of a two-step method (CO2 exposure for sedation followed by decapitation) is the recommended technique.
NOTE: Due to the anatomy of rat and mouse neonates, cervical dislocation is difficult to perform adequately, especially when euthanizing mice and rats in the “pinky” stage before hair grows in at 7-10 days. For routine purposes (such as assuring death after CO2 exposure) decapitation must be used rather than cervical dislocation.

http://www.utexas.edu/research/rsc/i...uideline03.pdf

Feeders cannot be decapitated of course, but the general method is there....