How Do Birds Eggs Hatch? (Full Process Explained)

Regardless of egg size, the “egg cycle” is roughly similar for all birds: a clutch of eggs is laid, hatched, and after a specific period of time (varies by species), the chicks hatch from the shell and the eggs begin to lay outside world life.

But what factors affect how long an egg needs to hatch? Can the eggs survive if they don’t hatch? If you want to learn more about the fascinating hatching process, read on.

After a period of incubation — from 9 days for the scabbard to 80 days for the royal albatross — the newborn chicks emerge from the eggs and peck their way out of the shell. Incubation is undertaken by the mother alone, alternately between the parents, or, in rare cases, by the male.

Artificial hatching is also used in commercial settings, with thermostatically controlled incubators maintaining the temperature required for chicken, duck, quail and pheasant eggs to hatch successfully.

Royal albatross eggs can hatch for up to 80 days

Once the egg is fully hatched and the embryo inside is sufficiently developed to be viable, the smallest holes appear in the shell, which are formed by a pointed cap on the beak of a newly hatched hatchling, called an egg tooth. This temporary anatomical feature allows the chick to knock from inside the egg and causes a crack to appear. The crack in the eggshell eventually widens, forming the chick’s exit point.

The chick usually doesn’t need any intervention during the hatching process, it can take some time from the first cracks appearing until the chick is ready to hatch, but it’s usually strong enough to do it on its own.

If you’re interested in learning more about the egg hatching process, read on and find out whether the egg grows larger as the embryo inside develops.

Fieldfare’s recently hatched chicks

egg hatching process

The timeline from laying to hatching is relatively common. Once a clutch of eggs has been laid, incubation follows, and while timing and heat sources may vary from species to species, the purpose and result are the same.

From inside the eggs, once the birds have developed enough to have a good chance of surviving, they show the first signs of hatching.

The main steps in the egg hatching process are as follows:

incubation

Once the fertilized eggs are laid, they need to be kept at a constant temperature for a certain number of days. The incubation period varies by species, but averages 12 to 15 days for most songbirds and double that for larger birds such as owls and kestrels.

To help regulate temperature, hatching birds grow what’s called a “brood zone,” the featherless area of ​​the bird’s abdomen that’s filled with blood vessels and is perfect for providing extra warmth to the hatching eggs.

Female american robin sits on nest and incubates eggs

final stage of embryonic development

The physical act of hatching in birds is triggered by the completion of embryonic development inside the egg. As the unhatched embryo forms, an anatomical feature called “egg tooth” develops; this pointed cap on the edge of a hatchling’s beak helps the chick break out of its shell, a process known as “pecking.”

emerge from the eggshell

The first external sign of hatching is tiny cracks or holes in the shell as the chicks begin to burst through the inside. By pecking in a circular fashion from within the shell, the weakest point is found, and tiny cracks open wider to reveal the bird’s head, then the rest of the body. In some species, this stage may take longer than 12 hours.

Ducklings hatching from their eggs

Cleaning the nest after hatching

Once the newly hatched chick is fully hatched from the egg, the mother bird usually removes all the eggshell fragments from the nest to make a little living space for the growing chick.

How long does it take for an egg to hatch in a bird’s nest?

The incubation time required for a bird’s egg to hatch successfully varies by species, with smaller songbird eggs taking less time to hatch than larger, heavier birds.

White-eyed or silver-eyed species have the shortest incubation period, with their offspring hatching in just 9 to 10 days. The eggs of northern cardinals and black-eyed rushes hatch for 13 to 14 days before hatching.

At the other end of the incubation period length are larger birds such as barn owls (29 to 32 days), golden eagles (41 to 45 days), California condors (53 to 60 days) and royal albatrosses (up to 80 days).

Oriental white-eyed chicks usually hatch within 10 days

Can bird eggs hatch without a mother?

In some bird species, the eggs are incubated solely by the father, including emus, cassowaries and emperor penguins.

Jacanas, dotterels, and phalaropes are polyandrous species, meaning that females mate with more than one male. For these birds, incubating and raising the young is the sole responsibility of the male. However, these species are relatively rare, accounting for only about 5% of all bird species.

Bird eggs do require incubation with an external heat source to hatch, and in the wild, this is hatched by either parent bird. An exception are cuckoo eggs, which are never hatched by mother cuckoos because they secretly land in the nests of other brood birds.

Another highly unusual anomaly in the bird world is the Mario, an extremely rare shorebird native to the Indonesian island of Sulawesi. The eggs are not hatched by the mother bird, but are laid in pits the mother dug in the hot ground and “baked” for 60 to 90 days before hatching, where the newborn chicks need to tunnel to the surface of the sand.

Poultry farmers rely on artificial incubators set at specific temperatures to successfully hatch eggs laid by chickens, ducks, quails, geese and pheasants. Under these conditions, no mother bird is present and the time necessary to allow the eggs to hatch is set.

Maleos bury their eggs in the hot ground

Do bird eggs hatch on their own?

If hatching is successful, the chicks will hatch without parental intervention. Once the chick is full-term and developed enough to survive in the outside world, it begins to peck at the eggshell and gradually emerges through the crack created by its beak.

Do Bird Eggs Grow After Laying?

Once the egg is laid, it doesn’t increase in size and actually lose weight over time as moisture is lost through the permeable shell. Interestingly, newly hatched chicks are lighter than freshly laid eggs.

Sandhill Crane sitting on the nest waiting for two more eggs to hatch, with a hatching chick nearby

What temperature do eggs need to hatch successfully?

Eggs need to be kept at a constant temperature a few degrees below the bird’s average body temperature to develop properly. The optimum temperature for the eggs of many birds is 98.6 degrees Fahrenheit (37 degrees Celsius), which is about the same as normal human body temperature.

If the temperature in the nest drops too far below this temperature for any period of time, there is a risk that the clutch will not hatch successfully.

Conversely, if the nest temperature is too high, there is a risk that the eggs will hatch prematurely and the newborn chicks will be underdeveloped and unable to survive.