Re: How many days old must a rat be before it can be euthanized via CO2?
Pinkies and fuzzy's aren't as susceptable to CO2, so putting them into a deep freeze is considered more humane thatn CO2 chamber. I believe I read on here that the co2 creates an acid when in the lungs of the pinkies and fuzzies. anything older than that is put down with co2.
Re: How many days old must a rat be before it can be euthanized via CO2?
It's the diving reflex - pinkies and fuzzies can hold their breath so using gas chamber will suffocate them. Not quick or nice. I've bred only mice, but I've used 10 days as a rule of thumb. Any older goes with CO2, any younger with other methods.