How long can chicken eggs stay cold?
Embryos have survived at temperatures below 90°F for up to 18 hours. You should continue to incubate the eggs after the outage; then candle them 4 to 6 days later to check for further development or signs of life. If, after 6 days, you do not see life or development in any of the eggs, then terminate incubation.
How long can bird eggs be left unattended? Most bird eggs will remain healthy for up to two weeks before incubation starts.
Fertile eggs should be stored between 55 and 65°F. If fertile eggs reach temperatures above 72°F, embryos will begin to develop abnormally, weaken, and die. Embryos stored below 46°F also have high embryo mortality. Room temperature is generally too warm and the refrigerator is too cold for storing fertile eggs.
Hatchability holds reasonably well up to seven days, but declines rapidly afterward. Therefore, do not store eggs more than 7 days before incubating. After 3 weeks of storage, hatchability drops to almost zero. Plan ahead and have a regular hatching schedule to avoid storage problems and reduced hatches.
Eggs which have been subjected to freezing conditions (in the coop or in shipping) will have suffered damage to their internal structures and are highly unlikely to hatch. Incubation during this time of year due to the temperatures will have to occur indoors with a stable temperature.
To keep bacteria to a minimum, the Food and Drug Administration (FDA) requires commercially sold eggs to be stored and transported below 45°F (7°C).
Incubator temperature should be 100–102°Faherenheit. In some incubators, 99°F is acceptable. 103°F and over will kill embryos. When you use a thermometer, place it in the middle of the incubator near the eggs on the screen — not under the screen or at the sides of the incubator.
The best thing you can do is respect the Migratory Bird Treaty Act and leave the egg alone. In most cases, it is unlikely the egg would hatch. If you know the egg is from a rare or endangered species, call your state fish and wildlife agency or a wildlife rehabilitator.
You'll see blood pumping through the heart of a tiny, developing embryo if you candle a fertile egg on Day 4. If the embryo dies at this point, you may still see a faint network of blood vessels inside the egg's contents. An embryo dying at this point will show a large, black eye.
A fertilized chicken egg can survive in a dormant state 10 days before it needs to be raised to around 99 degrees for the cells to start reproducing.
Does cold affect chicken egg laying?
Many hens stop or slow down egg production during the fall and winter. The lack of daylight and cooler temperatures tell their bodies to rest. Extension Poultry Specialist Jesse Lyons at the University of Missouri says if you want to convince your hens to keep laying, they'll need supplemental daylight.
The Bottom Line
With proper storage, eggs can last for at least 3–5 weeks in the fridge and about a year in the freezer. The longer an egg is stored, the more its quality declines, making it less springy and more runny.

Sometimes it takes longer and sometimes shorter times. I've had a hatch as late as day 25 (as in the image below). See here for more information about early birds and here for late. This chick hatched at day 25 and is now a perfectly healthy Golden Laced Wyandotte.
The longest incubation was recorded in the case of an egg of the mallee fowl (Leipoa ocellata), Australia, which took 90 days to hatch, compared with its normal 62 days.
The process of removing dead eggs while incubation is called 'Candling'. It involves shining a bright flashlight through the egg in a dark room. Upon close inspection, you'll see veins running through the egg in case it's alive. Hope you found it helpful!
Never leave cooked eggs or egg dishes out of the refrigerator for more than 2 hours or for more than 1 hour when temperatures are above 90° F. Bacteria that can cause illness grow quickly at warm temperatures (between 40° F and 140° F).
The rule of thumb? You can leave eggs on the counter about two hours at room temperature or one hour if the temperature is 90 degrees or hotter before you start to worry, per the Egg Safety Center. After two hours, you'd be safer to throw those eggs out and get a fresh dozen rather than chance it.
You don't need to refrigerate farm fresh eggs. Eggs are laid with a near invisible coating called the "bloom" or "cuticle" on the shell. What is this? This coating helps keep air and bacteria out of the egg, keeping the egg fresher longer.
160°F/70°C -- Temperature needed to kill E. coli and Salmonella. While Salmonella is killed instantly at temperatures above 160F keeping the temperature for longer periods of time at lower temperatures will also be effective.
As the USDA notes in Keeping Food Safe During an Emergency, your refrigerator will keep food safe for up to 4 hours during a power outage. Keep the door closed as much as possible. Discard refrigerated perishable food such as meat, poultry, fish, eggs, and leftovers after 4 hours without power.
Will eggs hatch at 102 degrees?
Incubator temperature should be maintained between 99° and 100°F. The acceptable range is 97° to 102°F. High mortality is seen if the temperature drops below 96°F or rises above 103°F for a number of hours. If the temperature stays at either extreme for several days, the egg may not hatch.
An egg in good condition can hatch without its parent. The best thing to do if you find one is to call your local wildlife rescue center and see if they are able to take it in. If the future chick belongs to a rare or endangered species, they might send someone out to collect it and raise it.
If you do not see any adults near the nest and there is no progress (no hatched eggs, etc.) after four (or more) weeks, the nest may have been abandoned. For a nest containing young, often nestlings may appear to be abandoned when they are actually not.
It has been illegal to take the eggs of most wild birds since the Protection of Birds Act 1954.
The best kept secret in determining an egg's freshness is to see if it sinks in water. To try the egg water test, simply fill a glass or bowl with cold water and submerge the eggs. If the eggs sink to the bottom and lay flat on their side, they're still fresh.
If you are not sure whether the embryo is alive, place the egg back in the incubator and retest later. A second test can be made after 14 to 16 days of incubation. If the embryo is living, only one or two small light spaces filled with blood vessels can be seen, and the chick may be observed moving.
When will the chicks hatch? Chicken eggs should hatch 21 days after they first start in an incubator. (Remember that your eggs have already been incubated for 14 days before you receive them!) Other bird species have different incubation times.
Chickens can survive quite well with temperatures down into the teens. In fact, if you place a thermometer in your coop overnight, you will likely find the temperature has been maintained in the thirty to forty-degree area. Each chicken has generated enough heat to keep themselves and their flock mates warm.
As for your chickens themselves, you should check them often during cold weather to look for signs of distress. Don't forget that in below-freezing temperatures and wind chills, chicken frostbite can happen and it often happens quickly. Ten minutes can be all it takes even in a cold-hardy chicken breed.
Hens are less likely to successfully brood when the weather is cold. Hens are less likely to successfully brood when the weather is cold. Whether you are expanding an existing flock or are new to backyard chickens, hatching and raising your own chicks is a fun and satisfying experience.
How do chicken eggs go bad?
As the bacteria enters the egg, it will reproduce and grow, feeding on the nutrients – particularly if you've left the eggs on your shelf or counter and not in the refrigerator. Eventually, so much bacteria gets into the egg that the insides turn black – and very stinky. Learn more about the insides of a chicken egg.
Black or green spots inside the egg may be the result of bacterial or fungal contamination of the egg. If you come across an egg with black or green spots discard the egg. Off color egg whites, such as green or iridescent colors may be from spoilage due to bacteria.
Conduct a sniff test
Eggs that have gone bad will give off an unmistakable smell, regardless of whether they are raw or cooked. If you can't already tell while the egg is in the shell, crack the egg onto a clean plate or bowl and give it a sniff.
If there are still unhatched eggs at day 21, don't despair. It is possible that timing or temperature went slightly awry, so give the eggs until Day 23. Candle any unhatched eggs to see if they are still alive before discarding them. Keep in mind that when hatching eggs, you will likely end up with roosters.
When should incubator lockdown take place? The generally agreed time is three days before the eggs are due to hatch. For normal sized chicken eggs this is at the end of Day 18 of incubation. Bantam eggs tend to hatch more quickly, at around 18 or 19 days into incubation, so should be locked down at around day 16.
Eggs must be turned at least 2-3 times daily during the incubation period. Many experts say if you can turn them 4-5 times a day it is even better.
Unwashed, room temperature eggs should keep for about two weeks. If you aren't planning to eat your eggs for a while, we recommend refrigerating them. The cooler temperatures increase the shelf life, with eggs keeping for up to three months in the refrigerator.