Natural incubation of poultry.
Incubation under a broody hen is the ideal way to hatch a small number of eggs, particularly where the expense of purchasing an incubator is not warranted. One of the difficulties is that a broody hen is not always available when she is needed.
Heavy chicken breeds or their crosses are the best hens for sitting on most eggs; for example, breeds like old English game crossed with an Australorp make good natural incubators.
A hen can successfully hatc h 12-15 eggs depending on her size. She will be able to cover 9-11 duck eggs or 4-6 turkey or goose eggs. A bantam hen will cover 8-10 eggs of her own or about 5 hen eggs. The hen turns the eggs and alters their position in the nest regularly to ensure even heating. If too many eggs are placed under the hen, the outside ones may not get enough warmth and during cold weather the embryo will be destroyed.
A hen will only sit in earnest once she has completed laying a full clutch, and once she has settled she should not be removed from the nest. She will get off when necessary to feed and water and go back before the eggs get too cold. If it is necessary to handle a sitting bird, remove her from the nest carefully. First, lift the wings to release any eggs that may be lightly held between the wings and the body. Failure to do this may result in broken eggs as they fall out when the hen is lifted. Next, pick the hen up with one hand holding her under the body and the other hand over her back. The hen should always be lifted from and returned to the nest head first. This reduces her resistance and prevents the wings catc hing on the sides of the nest box.
Other species – natural and artificial incubation.
Selection and care of eggs is important to achieve a good hatch. For detail, see Incubation – production and selection of eggs.
The principles and guidelines for incubation of chicken eggs apply to other species, except for some small differences. Egg size of other birds is different to that of fowl eggs and it may be necessary to make some modifications to the trays supplied in artificial incubators. For more detail on artificial incubation.
Turkey eggs should be collected frequently and in containers that will allow rapid cooling of the eggs. The turkey hen is a careless sitter and a dirty user of nesting arrangements. If eggs are left in the nest too long there will be a large number cracked or fouled and so it is recommended that eggs are collected at least every two hours if practical.
The nutritional requirements of the breeding turkey differ from those of the breeding hen. They have a greater need for vitamin A and riboflavin.
Turkey eggs should be turned end for end (not rolled) at least through 90°, preferably 180° but this requires manual handling of each egg and therefore could introduce disease.
Natural hatching can be carried out with broody turkeys or broody hens. A hen will sit successfully on 4-6 turkey eggs, whereas a turkey hen can handle 15-18 eggs. The incubation period is 28 days and some broody hens, especially those with experience of sitting on hen’s eggs, will get restless after the third week. Check to see that they do not stop sitting before the eggs hatch.
The turkey should be allowed to leave the nest at will and requires a nest box about 60 x 60 cm in a cool, quiet place. The nest should be lined with clean dry straw, grass or shavings and be treated with an insecticide to control lice and fleas before sitting begins.
In fan-forced incubators, best results have been achieved by reducing the temperature 0.1°C to 0.5°C below that recommended for hen eggs. It will be apparent whether a slightly lower or higher temperature is necessary after one or two hatches – if hatc hes are slightly late, a small increase in temperature is needed.
Slightly higher humidity about 60-62% is best for turkey eggs during setting and this may be increased to 70-77% during hatching. Extra moisture trays may need to be added to achieve this humidity.
Turkey poults usually take longer than chickens to emerge after pipping and give the appearance of a slow hatc h. Do not open the door or disturb eggs until the full 28 to 28.5 days have passed.
Most breeds of ducks have an incubation period of 28 days, but the Muscovy duck is an exception and requires 35 days. Ducks are dirty layers and it is important to clean the eggs as soon as possible through regular collections.
Great care should be taken in handling duck eggs as their shells are prone to cracking. It is essential to incubate eggs that have good shape and shell texture.
Natural incubation of duck eggs usually gives good results, whereas artificial hatc hing results are variable and often low.
A duck can cope with up to 13 eggs of her own, whereas a broody hen will only successfully incubate 9-10. Muscovies have a reputation for being good sitters and will cover 15-20 eggs.
The nest box needs to be small enough to prevent eggs from rolling away, but roomy enough to keep the duck comfortable. Single nests are preferred. They should be private so other birds will not interfere with the sitting duck. Provide more nest boxes than sitting ducks need.
The brooding instinct is so strong in Muscovies that some will sit on one clutch of eggs after another providing the hatchlings are taken away immediately. After weeks of sitting, the duck will lose condition and should be rested.
Water fowl should have access to a water supply for swimming in order to keep the eggs moist. If a suitable pond is unavailable or if the eggs are under a hen, the eggs should be sprinkled with warm water from the 15th day.
For fan-forced machines the usual temperature is 37.2°C to 37.5ºC with a relative humidity of 59% during setting, raised to 80% for hatching. The wet bulb readings for the above temperatures would be 30°C and 33.9°C.
The extra humidity requirement can be met by placing trays containing 12 mm of sand saturated with warm water on the floor of the incubator. The water should be replenished twice a day. During the hatching period it may also be necessary to place clean damp cloths over the eggs.
Water fowl eggs should be turned end for end (not rolled) at least through 90°, preferably 180° but this requires manual handling of each egg and could introduce disease.
Incubator capacity for duck eggs will be 80-85% of that for hen eggs; for example, a machine with a capacity of 150 hen eggs will take up to 130 eggs of Aylesbury ducks and 140 eggs of khaki Campbell or Indian runner ducks.
As geese are mainly self-supporting foragers, nutritional deficiencies are unlikely to occur. When pasture is in short supply during winter and early spring, it is beneficial to provide a mixed poultry ration as well.
The incubation period varies from 30 days in the smaller breeds such as Chinese and Egyptian to 33-35 days in the larger breeds such as Emden and Toulouse. There is a much greater range in incubation length with geese and hatching may be expected 2 or 3 days earlier or later than the mean times quoted.
For optimum fertility in breeding geese, the birds should have free access to water from a pond or slow-running stream, and the mating ratio should be one gander to three to four geese with the heavy breeds and to five geese for the light breeds.
A goose can cover 10-15 eggs and is an excellent sitter. Muscovy ducks are satisfactory for hatc hing geese eggs because they are similar in size to geese. A broody hen is able to cover 3-6 geese eggs but will have difficulty turning the eggs, so this should be done for her at least three times each day, preferably when she leaves the nest to eat and drink.
Plenty of moisture is necessary. Eggs set under a hen should be sprayed with warm water daily from the 15th day unless the sitting geese have access to suitable swimming area.
Fan-forced incubators give the best results at 37.2°C with a relative humidity of 70%.
Eggs should be turned through at least 90° (not rolled) 3 or 5 times a day for the first 26-30 days, according to the breed.
Goslings should be removed from hatching trays as soon as possible to stop them interfering with the safe emergence of others.
The incubation period for Guinea fowl eggs is 26-28 days, and 24-25 days for the crossbreds. Eggs can be hatched either naturally or artificially.
Fertility is a problem for Guinea fowl that are kept in small pens; however, fertility can be increased by giving the birds access to free range. For ease of egg collection, it is best if the birds are let out to range after midday. Egg handling prior to incubation is important. Eggs should be collected at least twice daily; discard the very dirty ones. Dry cleaning with fine steel wool is the best method of cleaning eggs for hatching. Eggs should be fumigated shortly after being collected and cleaned. They are then held at 12°C to 15°C for up to seven days before setting, as at temperatures above 18°C the embryos can start developing, causing uneven hatching or many early embryonic mortalities.
Guinea fowl hens make poor mothers if they don´t have privacy and are best left to sit where they choose. A Guinea hen will cover 12-15 eggs. Ordinary hens may be used as sitters. They will manage 20-28 Guinea fowl eggs.
Artificial incubation requirements slightly lower than those used for fowl eggs are satisfactory. When eggs are hatc hed artificially the temperature should be 37.2°C with a wet bulb reading between 27°C to 31°C for the first 24 days of incubation for pure Guineas or 21 days for crossbreds. The incubator vents are then closed enough to give a wet bulb reading of 32°C to 34°C at hatching while the temperature is dropped to 36.1°C. Eggs must be turned an odd number of times (minimum of three times) each day for the first 24 days for pure Guineas and 21 days for crossbreds.
Eggs should be candled at 9 or 10 days and infertiles, with dead embryos removed and the remainder fumigated. Embryos are susceptible to damage from fumigation between 12 hours and 4 days after setting and pipping has commenced.
The incubation period for pheasants varies from 23 to 26 days depending on the variety. Pheasants are not reliable sitters and it is best to collect their eggs as soon as they are laid and to hatch them either under a foster mother or in an incubator.
Broody bantam hens can be used to hatch pheasant eggs and will cover a clutc h of 8-10 eggs. It is best to set clutches of the same pheasant variety or incubation period otherwise the foster mother may leave the nest before the eggs with the longer incubation period have hatched. Different incubation periods can be overcome by setting eggs with a longer period first so that all eggs hatch together.
Some breeders set fertile bantam eggs with the pheasant eggs several days after setting the latter. Their reasoning is that they all hatch together and the bantams, being more precocious than the pheasant chicks, will teach them where and how to feed, to find warmth and educate them in parent recognition.
Humidity may be a problem during incubation, depending on the location. If it is, the eggs should be dampened slightly on alternate days the 9th day onwards. On the 18th or 19th day, the clutch can be well sprinkled with warm water.
The temperature for artificial incubation is 0.1°C below the maker´s recommendation for fowl eggs. It is best to hatch eggs in a separate machine or hatching compartment. Using fan-forced incubator and transferring the eggs to a hatcher on the 21st day may be preferred. humidity requirements are higher than those for fowl eggs, being 60% plus relative humidity during incubation and 80-90% during hatching.
Japanese quail will seldom sit on their eggs and they are best hatched either naturally under another species or artificially. The incubation period is 16 – 18 days. Bantams are the best sitters for natural incubation of quail eggs.
The temperature and humidity in fan-forced incubators are the same as for chicken eggs.
Newly hatched chicks often tend to straddle their legs in hatching trays with a smooth surface. To prevent this, fasten fine mesh material the bottom of the tray.
The incubation period for peafowl is 28 days. They make good mothers and will rear their chicks until 5 to 6 months old. Peafowl eggs can be successfully hatched under hens. The artificial incubation requirements are the same as those for turkeys.
Partridge eggs may be incubated naturally or artificially. The incubation period is 24 days. Incubator requirements are similar to those for chickens.
Table: The incubation period and mating ratio for various species of poultry