Decrease in Hatchability of Pheasant Eggs Associated with Enterococcus faecalis

A game bird producer in the North Central region of the United States submitted unhatched ring-neck pheasant (Phasianus colchicus) eggs for diagnostic evaluation. The submitting complaint was a drastic drop in hatchability. This operation has its own breeder birds that are housed in outside pens. This hatch occurred in the latter third of the production cycle. Typical hatchability for this operation is around 75% (± 3%). The hatchability of this hatch was between 14%-15%. Approximately 30,000 eggs were set with an expected hatchability of about 23,000 birds. The number of birds from this hatch was less than 4500, with a net loss approaching 20,000 chicks. All unhatched eggs submitted were in late stage development. The chick embryos had pipped through the shell but died before hatching. Approximately 5000 eggs originating from an outside breeder source were also set at the same time in the same machines and experienced a normal hatch. The exterior surfaces of the eggshells of the unhatched eggs experiencing low hatchability were swabbed and submitted for bacteriologic evaluation. Additionally, embryos from some of the unhatched eggs were removed aseptically from their eggshells, and their internal organs were harvested and submitted for bacteriologic evaluation. The bacteriology results identified no pathogenic bacteria from the eggshells. However, the embryo samples revealed large quantities of Enterococcus faecalis. In discussions with the producer, the only factor identified was an unusually warm period followed by an atypically cold and wet period during the time of egg collection for those eggs experiencing low hatchability.