Seen the site Chris. Sorry it's still suffocation to me and hardly humane. They will be fighting for Oxygen until they become unconscious. Same effect as drowning. The site points out that chickens, at the time of writing, were not covered by the humane regulations. I know they commercially kill chicks that way, but that doesn't sit well with me either. Still, its better than the pre-Salmonella scare ( pre-Edwina Curry) method of putting them live into the meat grinder and then feeding the bits to the battery hens.