Methods for treating poultry during processing for increasing the weight of the poultry are disclosed. The methods may be performed in a chill tank or other reservoir and utilize either equilibrium peracetic acid or non-equilibrium peracetic acid. The non-equilibrium peracetic acid may be prepared from hydrogen peroxide and a liquid acetyl precursor, such as triacetin. The methods comprise contacting a poultry carcass with peracetic acid-containing water at a pH of about 6 to about 9. The methods result in an increase in the weight of the processed products and an increase in a processing plant's percent yield of the processed products.