| | Background
Cool storage of hatching eggs is a "necessary evil" which hatchery managers have to endure. When coordinating the incubation of millions of eggs it is sometimes necessary to store hatching eggs, there-bye putting the development of the chick embryo "on hold". This storage does not come without a cost. Hatchery managers are aware of the general "rule" that the hatchability of eggs stored more than one week is reduced.
There is no data on modern strains to show how much hatchability declines as storage progresses. The present study was conducted to fill this information void.
Approach
Broiler breeder eggs (4032) were collected from a commercial flock at peak production. The eggs were divided into 8 groups of 504 eggs and stored for 2, 4, 6, 8, 10, 12, 14, or 16 days. A portion of eggs from each storage group was weighed regularly during storage. All eggs were incubated and the fertility, hatchability and incidence of embryo death calculated.
Results and discussion
Fresh egg weight was not different between any of the 8 egg storage durations. Egg weight loss increased with each 2-day increase in storage (Table 1). Egg storage did not significantly reduce hatchability when eggs were stored for a maximum of 6 days. However, after 8 days of storage, there was a significant decrease in of fertile eggs, and an increase in late period embryo mortality (between incubation days 15-21) (Table 2). Hatchability and late period embryo mortality again leveled off between 10 and 16 days of storage.
Table 1. Egg weight loss during storage and incubation.
| Storage length (days) | Fresh egg weight (g) | Post-storage egg wt. (g) | Loss during storage (g) | transfer egg wt (g) |
| 2 | 62.9 | 62.6 | 0.30 | 54.5 |
| 4 | 62.9 | 62.6 | 0.37 | 54.3 |
| 6 | 62.8 | 62.3 | 0.48 | 54.3 |
| 8 | 62.7 | 62.2 | 0.55 | 53.9 |
| 10 | 62.9 | 62.2 | 0.63 | 53.8 |
| 12 | 62.8 | 62.1 | 0.71 | 53.7 |
| 14 | 62.7 | 61.9 | 0.81 | 53.3 |
| 16 | 62.7 | 61.8 | 0.91 | 53.4 |
Table 2. Fertility, hatchability and embryo death due to storage.
| Storage length (days) | Fertility (%) | Hatch. of all eggs (%) | Hatch. of fertile eggs(%) | Embryo mortality day 1 - 7(%) | Embryo mortality day 8 - 14(%) | Embryo mortality day 15 - 21(%) |
| 2 | 95.8 | 78.9 | 82.5 | 3.1 | 1.4 | 6.6 |
| 4 | 95.2 | 76.2 | 79.9 | 1.7 | 3.3 | 7.7 |
| 6 | 93.9 | 74.1 | 78.9 | 2.7 | 1.8 | 8.0 |
| 8 | 93.4 | 65.7 | 70.5 | 2.4 | 2.0 | 12.5 |
| 10 | 94.4 | 68.0 | 72.3 | 2.0 | 2.3 | 13.7 |
| 12 | 90.0 | 63.7 | 71.1 | 4.1 | 3.0 | 13.5 |
| 14 | 92.3 | 66.5 | 71.9 | 3.9 | 3.3 | 14.9 |
| 16 | 90.9 | 61.8 | 68.0 | 5.1 | 3.3 | 17.0 |
Summary
Hatchery managers know from experience that the hatchability of eggs is reduced when eggs are cool stored for more than 7 days. The results of this study confirm practical experience and show that eggs stored for 2, 4, or 6 days have the same hatchability. There is a significant drop in hatchability when eggs are stored for 8 days versus 6 days, but no further drop in hatchability occurs when eggs are stored for 10, 12, 14, or 16 days.
Take home messages
| 1. | If you have to store eggs, limit the total storage on-farm and at the hatchery to 6 days. |
| 2. | If you have to store eggs more than 6 days, expect about a 8% drop in hatchability at 8 days of storage. |
| 3. | The rate of decline in hatchability is relatively slow for the first 6 days, followed by a big drop, and relatively slow for the next 6 days. Eggs stored for 10, 12, or 14 days have similar hatchability. There appears to be less urgency to set eggs after the big drop in hatchability after 6 days of storage occurs. |
| 4. | Although not statistically significant, there is another drop in hatchability and increase in embryo mortality when eggs are stored for 16 days. There should be a conscious effort not to store eggs longer than 14 days. |
Acknowledgements
Funding for this project was provided by the Canadian Broiler Hatching Egg Marketing Agency, the Alberta Chicken Producers, the Alberta Agricultural Research Institute. Broiler breeder eggs were donated by Maple Leaf Hatchery and Chick 'n Dale Poultry.
Source: Poultry Research Centre News - Vol. 8 No. 4, October 1999 |
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