Do you know of any people that have done away with themselves with helium or C02 buildup?
Sadly yes I have known people that used a gas exit from life and I have also euthanized several animals over the years using said techniques myself... I have also seen numerous unedited videos on humans as well as animals being euthanized/suicide by helium/nitrogen/CO2/CO, they are out there in a Google search for anyone to see... And last but not least I have 2 years pre-med in college, that I draw upon... It's not simply my baseless opinion that it's painless and not cruel it's backed by science and medical fact, it's actually quite peaceful...
I'm willing to bet gassing a bird and watching it simply go to sleep is a lot less emotional and stressful than the actual act of holding it down and whacking the head off and having blood everywhere, but that is just my opinion...
@mightymax the gas released by the vinegar and backing soda is CO2 (same as dry ice) and the end result is the same a peaceful sleep, as you said in this case the CO2 is heavier so the chamber is built in reverse...