If you search through any online forum related to incubation you will find countless posts that contain basically the same question stemming from the same issue. “My power went out; will my eggs be okay?” Weather problems and other issues can cause a breeder undue anxiety, and we are here to help alleviate some of that worry. So, if the power goes off, what damage is likely to have been done? Will the eggs be okay? Below is more information regarding this topic. Feel free to get in touch with Brinsea, The Incubation Specialists, if you have any further questions. 

Temperature Zones

While worrying about an emergency power outage, keep in mind the fact that many breeders employ periodic cooling during incubation. In nature the hen must occasionally get off the egg, so occasional cooling is not necessarily detrimental. However, there are certain temperature zones that can spell disaster for your eggs. We will first cover the different zones and what they mean before we dive into handling a power outage. 

There are five temperature zones, identified by H. Lundy, that are characterized by having a major effect on a developing embryo. These zones are not clearly defined, rather, there is some overlap and blurring of the limits. They can, however, be used as a general guide. Below is a graphic that gives an idea of the area the zones encompass. This data is based on an incubator with a fan that is being used to incubate chicken eggs. temperature zones

Zone of Heat Injury

This zone has little to do with power outages, but it is important to note nonetheless. This zone is right around 104.9°F. Continuous temperatures at this level will effectively kill all developing embryos. Short periods of high temperature, however, may not be lethal. The older the embryo the more tolerant it will be toward high temperature spikes.

Zone of Hatching Potential

This zone is the recommended ideal temperature for incubation and hatching. This includes a range of 84.5° - 104.9°F. Within this range there is a possibility for eggs to hatch, although 99.5°F is the ideal temperature for hen eggs. That is why this is referred to as the zone of hatching “potential.” Above or below 99.5°F and there is a risk for deformities. 

Zone of Disproportionate Development

Even outside of the incubator, eggs stored above 80.6°F will begin to develop. In order to avoid this happening, proper egg storage and handling procedures can be followed. During incubation, eggs that are continuously kept at a range between 80.6° - 95°F. The embryo will develop, but it will be disproportionate in the sense that some parts will develop faster than others. Typically, the heart and head will be enlarged while the rest are delayed. Most embryos will not survive if this occurs. 

Zone of Suspended Development

Suspended development is usually intentional, because this is the temperature zone where eggs should be stored prior to incubation. The range is 28.4° - 80.6°F, although the ideal temperature for storage is 59°F.

Zone of Cold Injury

Below 28.4°F is known as the zone of cold injury. In this zone ice crystals will start to form on the egg and permanent damage may be done to the internal structures. However, eggs may lie close to freezing for a considerable amount of time before suffering damage. 

Continuous vs. Periodic

The above information deals mainly with temperature zones that are continuous. Long periods of time in certain zones can cause a high mortality rate as well as deformities. Eggs that only periodically encounter less than ideal circumstances are a different story. Below are a few conclusions that have been drawn from scientific research regarding overheating or chilling eggs during incubation.

  1. Cooling eggs for short periods (30 to 40 minutes) every 24 hours after the first seven days during incubation has no detrimental effect and may be of benefit. Some of our incubators come with a cooling feature just for this purpose.
  2. Eggs that are likely to be cooled for a period longer than two hours (as in during a power outage) will need to be treated differently depending on their stage of development. We will cover this in greater detail in a moment.
  3. Overheating is more of a danger than cooling, especially during the first week of incubation.

How to Handle a Power Outage

If you experience a power outage longer than two hours during the first few days of incubation, it is actually better to chill the eggs and get them in a range of 41° - 68°F. This can easily be accomplished by putting the eggs in the refrigerator. 

This method can be followed up until the 14th day of incubation, although losses can be expected the further along the eggs are. Another option, especially late in incubation, would be to take steps to limit heat loss. This can be done by keeping the lid on the incubator and raising the temperature in the room. The metabolic heat of the embryos will keep them warm for a little while after the power goes out.

More Information

Not necessarily important toward the topic of handling a power outage, but something that may be interesting to some, is how periodic cooling affects different species. In nature, as already mentioned, the mother hen must get off the eggs occasionally to eat and drink. It is speculated that this cooling may stimulate the embryo to develop, which is why it is beneficial. 

Through artificial incubation, however, this cooling has been effectively bred out of chickens. We have noticed, therefore, that duck and geese embryo respond much better to periodic cooling than chicken eggs. It follows that totally wild species will be more susceptible to periodic cooling than species that have undergone commercial breeding.

Hopefully these explanations will enable bird breeders to assess the likelihood of damage from accidents. It should certainly allay any fears about the cooling that may accompany the manual turning or inspection of eggs. 

If you have more questions you can reach us at (888) 667-7009, or via Facebook or Instagram messenger. Happy hatching!