Analyzing Data:

Egg storage is unavoidable in the broiler breeder industry.  Studies reported in the Commercial Chicken Production Manual by North and Bell indicated the decline in hatchability with prolonged egg storage.  While development of the embryo is stalled during cold storage this study reported as much as a nine percent decrease in hatchability of fertile eggs when stored for seven days and it gets more severe when eggs are stored for longer. Additionally, chick hatch times can be delayed by as much as four hours when eggs are stored for 10 days prior to setting. This can also reduce chick quality and livability.

It is obvious from my records that the refrigerated eggs showed a significantly higher number of deaths due to bacteria and had the lowest weight before hatching.  Refrigeration had unfavorable effects on hatchability.  This could be for many reasons including cleanliness of storage environment, the humidity being set too high or too low during storage or improper temperature during the holding period.  The refrigerated eggs were a week older but cell division is stalled under controlled conditions during storage.  The genetics could also be a factor as well as illness or disease in the hen.    

Because I used a cardboard box, instead of a store bought incubator, there was some variance in temperatures, especially at night.  This is the probable cause of such low hatching rates.  When I do this project again in a classroom, I will first invest in a thermostat to regulate heat, or I would make sure the box is in a warmer part of the room to produce better results.  The overall hatchability was only 24% of the total number of fertile eggs, that is about 1 out of every 4.  The mortality rate for the fresh set was 50% and for the refrigerated set, a whopping 94%.  This leads me to believe that the eggs were not properly stored.

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