For laying hens, nest boxes just large enough to fit one seated hen are desirable. If eggs are to be collected for consumption, efforts should be made to decrease broodiness in hens. The term “broody” refers to a hen that stops laying eggs so that it can sit on eggs, even when no eggs are present. As soon as this behavior is noticed, the hen should be moved to a wire cage. Broody hens can have an aggressive temperament, and caution must be taken during handling. Most hens put into cages become less broody in 2–3 days. Without intervention, hens can remain broody for 3–4 weeks.
Backyard flocks raised under natural light stop laying when the number of daylight hours decreases and undergo a molt period (typically lasting 3–4 months but sometimes longer). If they are provided supplemental lighting, most chickens lay eggs for approximately 1 year before going into a molt. Artificial lighting can be used to induce layers to lay eggs during winter. This strategy increases the number of eggs laid during that period but not the total number of eggs laid.
With artificial lighting, typically, lights are on for 13–16 hours per 24-hour period, or they're on constantly. Continuous lighting removes the cue of increased daylight hours that usually stimulates molting hens to start laying again. Supplemental lighting also increases the risk of cannibalism in birds not individually caged, because continuous lighting tends to make birds more stressed and irritable.
As long as feather loss is not associated with insect infestation, reddened or abraded skin, poor nutrition, or open wounds, lengthy or bizarre-appearing feather loss can be attributed to an "unusual molt." If desired, hens exhibiting unusual molts can be culled from the flock. In general, after an unusual molt, even the most productive egg-laying hens approach only approximately 70% of their former production level in a subsequent production period. All hens should molt at least once a year. If they do not molt naturally, molt can be induced by decreasing the hours of light.
Incubation and Hatching of Eggs in Backyard Poultry
Probably the greatest factor that determines whether to buy hatched chicks or to hatch eggs within a backyard poultry flock is the desired size of the flock. For small flocks, inexpensive, easy-to-operate incubators/hatchers are available at farm stores, through catalogs, or online. When a flock is first being established, up to 50% of the eggs might not hatch, making egg space a concern if a large hatch is needed.
Most home incubators have good temperature control but inadequate humidity control. Chicken eggs can withstand changes in humidity during incubation; however, eggs of other poultry species (eg, turkeys) are much more sensitive to humidity fluctuations. With home incubators, the temperature should be regulated for at least 2–3 days before eggs are placed in them.
During incubation, the temperature should be checked twice daily. Fluctuations between 36.7°C (98°F) and 38.3°C (101°F) are acceptable for chicken eggs; temperature requirements for other species should be researched before incubation. In addition, the water pan should be kept full to maintain constant humidity.
Unless they have dark shells, eggs should be candled at least once during incubation, typically after the first mortality peak, at 7–10 days of embryonation. Candling consists of shining a light through the egg to determine embryo viability by detecting movement of the embryo and presence of blood vessels.
Fertile eggs candle dark except in the area of the air cell (air sac), with visible blood vessels and a dark spot representing the live embryo (see fertile egg image).
Courtesy of Dr. Yuko Sato.
Infertile, or “yolker,” eggs will candle through, showing only a slight shadow for the yolk and having no internal structures and no embryonic development (see infertile egg image).
Courtesy of Dr. Yuko Sato.
Eggs containing embryos that died with no positive development can candle through as yolker eggs do. Dead or nonviable embryos can have a blood ring around the embryo that is due to the movement of blood away from the embryo after death (see nonviable embryo image).
Courtesy of Dr. Yuko Sato.
Dead eggs can be removed before possibly exploding. Eggs need to be turned approximately every 6 hours until the last few days before they hatch (embryonation day 18 for chicken eggs).
Knowing approximate incubation periods of the poultry of interest helps to gauge when to provide adequate interference for a successful hatch. For example, the incubation period for chickens is 21 days; for bobwhite quail, 23–24 days; for guinea fowl, 27–28 days; for ducks, 28 days; and for geese, 28–33 days. If eggs do not hatch, examination of the dead embryos can yield some clues as to the cause.
Common problems encountered during incubation and hatching of poultry eggs include the following:
early death (due to infertility, too-long or improper storage before incubation, extreme temperature fluctuation)
late death but not pipped (because of extreme temperature fluctuation, poor humidity) ("pipping" refers to the chick's breaking through the eggshell to hatch)
pipped but dried and stuck to the eggshell (generally because of poor humidity in late incubation or during the hatching period, or because of a weakened embryo from temperature fluctuations)
pipped but drowned in egg fluids, or malpositioned embryo (because of turning malfunction during incubation)
After hatching, chicks should not be moved until dry and fluffed. Occasionally, chicks hatch that have not completely absorbed their yolk sac. These chicks have a poor chance of survival, and euthanasia is warranted.
If possible, all chicken chicks should be vaccinated for Marek's disease as early as possible—either in ovo or at the hatchery (see Vaccination of Backyard Poultry).
For More Information
Purina Animal Nutrition: Hatching Eggs at Home: A 21-Day Guide for Baby Chicks
North Carolina State University Extension: Backyard Flocks & Eggs: Incubation & Hatching
Lyons JL. Small Flock Series: Incubation of Poultry. University of Missouri Extension; 2003.
