Method of stunning pigs using gas and slaughterhouse for slaughtering pigs

A method of stunning pigs using gas, the method comprising the following steps:

• (A) preparing the pigs for the gas-stunning procedure of the pigs;
• (B) gas stunning the pigs in a gas-stunning chamber, after step A;
• wherein step A comprises the steps of:
• (A1) providing pigs in crates in which at least two pigs and at most ten pigs are present in each crate;
• (A2) keeping the pigs in the crates in a relaxation chamber, wherein each crate containing pigs remains in the relaxation chamber for a dwell time t1, wherein t1 is at least 30 minutes;
• (A3) conveying the crates containing the at least two pigs from the relaxation chamber to a conditioning chamber, in which conditioning chamber the O2 vol % is lower than 13% and higher than 6%;
• (A4) keeping the pigs in the crates in the conditioning chamber, wherein each crate containing pigs stays in the conditioning chamber for a dwell time t2, wherein t2 is at least 3 minutes;
• (A5) conveying the crates containing the at least two pigs from the conditioning chamber to the gas-stunning chamber.