ELISA kits have been used to detect antibody in egg yolk. The major advantage eggs offer over blood samples is the ability to collect samples without compromising flock biosecurity. A disadvantage to using egg yolk over sera concerns the method of preparing yolk for antibody testing. The technique used in this study involved a simple dilution method with no mixing or extraction. To determine the adequacy of yolk samples to replace serum samples, a serum sample and the first six eggs were obtained from each of 50 commercial leghorn hens. Mean titers were consistently larger for serum than for yolk, but the size of the difference varied with the virus. The variation of mean egg titer was comparable to that of the serum titer. Correlations between a hen's serum titer and the mean titer from hen eggs were only moderate, ranging from 0.35 to 0.85 across viruses and systems. The ability to predict the serum titer of a single hen by the mean titer from hen eggs may be inadequate.