The invention relates to a method for the non-therapeutic treatment of poultry for the purpose of reducing the conversion rate of the feed used to raise the poultry. The treatment comprises orally administering at least one glycine compound to the poultry, which glycine compound corresponds to the following formula (I) or to a salt thereof : wherein R and R are independently an alkyl, an alkenyl or a hydroxyalkyl radical containing 1 to 18, preferably 1 to 6 carbon atoms or wherein R and R form jointly together with the N atom a heterocyclic 5- or 6-membered ring. The glycine compound is preferably N, N-dimethylglycine (DMG). The invention also relates to the therapeutic and second medical use of that glycine compound to reduce the incidence of ascites, and to a feed for poultry containing an amount of that glycine compound.
