Furthermore, the production of standardized IgY, although theoretically and technically relatively simple, is labour demanding and, thus, cost intensive. Therefore, producing highly specific IgY in the most cost-effective manner possible is a key to justify commercial application of these antibodies. For example, this can be achieved by improving the immunostimulatory effect and the choice of the adjuvant used in IgY production in order to maximize the production of specific IgY (Lévesque et al., 2007). It may be possible as well to develop IgY directed against a mixture of poultry common pathogen microorganisms (Chalghoumi et al., 2008).