Quails, which are small ground-dwelling birds, do sit on their eggs, but this reproductive behavior is highly inconsistent depending on the species and its history of domestication. The act of a female quail sitting on a clutch of eggs to warm them is known as incubation, and it is a necessary process for the successful development and hatching of the embryo. Without the precise transfer of heat and moisture, the eggs will not develop to term. However, the presence of this natural instinct is not universal across all quail kept today.
The Instinct of Broodiness
The drive for a female bird to sit on a nest is known as broodiness, controlled by hormonal shifts within the hen’s body. A surge in the hormone prolactin, released by the pituitary gland, acts as the biological trigger for this behavior. This increased prolactin level also has an anti-gonadal effect, causing a hen to stop ovulating and laying new eggs, thereby diverting her energy toward nesting.
The hen begins to develop a “brood patch,” which is a featherless area of skin on her belly that becomes engorged with blood vessels. This patch allows for direct, efficient heat transfer from the hen’s body to the surface of the eggs.
The Process of Natural Incubation
Once a hen commits to the nest, she provides the precise physical conditions needed for the embryos to mature. She selects a sheltered location, often a shallow scrape lined with grass or debris, to offer security and help regulate the surrounding temperature. The quail hen uses her brood patch to maintain the egg temperature within a narrow range, typically around 99.5°F to 101.5°F (37.5°C to 38.6°C).
Humidity is also a factor, as the eggs must lose a specific amount of moisture through their shells to hatch successfully. The hen manages this by choosing nest material and leaving the nest briefly to forage, which allows the eggs to cool and be exposed to ambient humidity. She turns the eggs regularly to prevent the embryo from sticking to the shell membrane and to ensure uniform heat distribution. The duration of this process varies by species but generally takes between 16 and 23 days from the time the clutch is complete.
Species Differences and the Impact of Domestication
Whether a quail will sit on its eggs depends on its genetic lineage and how intensely it has been domesticated. Wild quail species, such as the Bobwhite or California Quail, retain a strong broody instinct and reliably incubate their eggs when environmental conditions are right. These species have not been subjected to the same selective pressures as commercial varieties.
Conversely, the Japanese Quail, or Coturnix Quail, the most commonly kept species globally, has largely lost its maternal instincts. This loss is a direct result of centuries of selective breeding aimed at maximizing egg and meat production. Breeders prioritized hens that laid year-round, inadvertently selecting against the broody behavior that naturally causes egg-laying to cease. Hobbyists who keep Coturnix rarely observe a hen successfully completing a natural hatch, even when a suitable environment is provided.
Natural Incubation Versus Artificial Hatching
Comparing the two methods reveals trade-offs for those looking to hatch quail chicks. Natural incubation offers the advantage of superior environmental control, as the hen instinctively adjusts the temperature and humidity. Chicks hatched naturally also benefit from immediate maternal care, learning foraging behaviors and receiving warmth, eliminating the need for a separate artificial brooder.
However, the disadvantages of natural incubation are significant, especially with domesticated quail. The hen can only cover a limited number of eggs, resulting in a lower overall yield compared to a machine. There is also the risk of nest abandonment due to stress, disturbance, or inexperience, common with breeds that have weak instincts.
Artificial incubation, using a machine, allows for the hatching of large batches of eggs on a predictable schedule, necessary for commercial operations or non-broody breeds. The artificial method requires technical monitoring of temperature and humidity, which must be precisely maintained at around 99.5°F throughout the 16-to-23-day period. While it provides high-volume hatching, it lacks the immune benefits and learned skills a chick gains from a mother hen. Artificially hatched chicks must be immediately transferred to a brooder with supplemental heat and water.