In our research into the therapeutic benefits of IgY, and its role as a potential treatment option for citrobacter infection in mouse models, it became necessary to determine the amount of time that IgY remains active in the mouse’s digestive system. This is important because IgY forms complexes with harmful intestinal bacteria (citrobacter in our study) and is subsequently passed from the mouse’s body. Therefore to accurately and efficiently provide scheduled oral administration of IgY to infected mice, it was necessary to determine the time span between oral administration and the passing of the antibody. It is understood that IgY is similar in function to IgG. Therefore it was hypothesized that the period of IgY’s presence in the digestive system would be similar in length to that of IgG’s, which has been established to be around 9 hours. To determine the exact duration, we fed healthy mice a normal therapeutic dose of IgY. Fecal samples were then collected every thirty minutes for fifteen hours. Each fecal sample was then broken up in coating buffer and coated onto polycarbonate well plates. Fecal samples were then subjected to enzyme-linked immunosorbent assay protocol using an enzyme/substrate induced color change to establish the presence of IgY in fecal samples. The data from this experiment was then used to establish further protocol for IgY treatment in mice.