The invention provides a method for vaccinating one or more avians in need thereof. The vaccination method comprises administering to the one or more avians a stable foam in an amount effective for inducing a neutralizing immune response against an infectious pathogen in the one or more avians. The foam comprises a gas and a liquid, and the liquid comprises a vaccine and a foaming agent. The avian may be a chick. Also provided is a method for preparing the stable foam.