Guinea hens start to lay in the spring (with increasing daylight) and continue laying for about 6-9 months. The egg laying period can be extended and early fertility improved by using artificial lighting. Domesticated guinea breeding birds are usually allowed free-range. However, on some farms the breeders are kept confined during laying period in houses equipped with wire-floored run porches.
They are difficult to confine in open yards unless their wings are pinioned or one wing is clipped. In their wild state, guinea fowls mate in pairs. This tendency prevails also among domesticated guineas if males and females in the flock are equal in number.
Artificial insemination of breeders is practised in some countries such as Australia. The birds are kept in cages with males being individually caged. Because of the small volume of semen from guinea males, domestic roosters (Gallus sp.) are often crossed with guinea hens. The crossbred will grow as large as the fowl parent, while retaining the gamey flavour. Hatchability tends to vary with the strain of rooster used. The offspring’s of the cross called “Guin-hens” are sterile and look like a turkey cross.
Under domestic conditions, it is not necessary to mate the birds in pairs to obtain fertile eggs. High ratios of females to males result in poor fertility. Higher fertility rates are obtained in flocks where male to female ratio is 4-5 or of six females. According to United States Department of Agriculture (USDA), when guineas are kept closely confined, one male may be mated with six to eight females and several hens will use the same nest. However, a ratio of 1 male to 5 females appears to give optimal fertility.
A breeder mash containing 22 to 24% protein should be made available to the birds, beginning about a month before eggs are expected. A good commercial chicken or turkey mash will give satisfactory results, with birds either on range or in confinement, when fedin accordance with the manufacturer’s directions. Clean fresh water should always be available.
The number of eggs a guinea hen will lay depends on her breeding and management. A hen that is of a good stock and is carefully managed may lay 100 or more eggs a year. Generally, breeders produce well for 2 to 3 years; sometimes they are kept as long as 4 to5 years in small flocks. In such flocks, hens usually lay about 30 eggs and then go broody. Selection of breeders for egg and meat production traits, as practised with chickens, would likely result in considerable improvement.
The economical traits of guinea fowl reported in literature are presented in Table 1.Guinea fowl can begin to lay as early as 16-17 weeks. In tropical Africa, laying only occurs during the rainy season and few weeks that follow. A clutch size of 12 to 15 eggs is common. Guinea fowl egg is smaller than that of hens, and on average weighs 40 g and has very hard shells which are difficult to test for fertility by candling. The hardness of eggshell may cause problems with artificial incubation.
Incubation period is 26 to 28days. The average weight of a keet at one-day-old is 24.62 g while live weight of 1.48 kgis achieved at 16 weeks of age. In the temperate climate laying period for guinea fowls is40 weeks. Caged guinea hens could lay 170 – 180 eggs per annum, of which 150 are fit to incubate to produce 110 keets. A hen reared on the soil lays 70 to 100 eggs per annum, which can produce 40 to 60 keets.
Table 1 Some production traits of guinea fowl
Egg laid per year (number) 100
Egg weight (grams) 40-45
Egg fertility 75-80
Egg weight/body weight (%) 2.8
Mature weight (kilograms) 1.6-1.7
Sexual maturity age (days) 186
Incubation period (days) 26-28
One-day-old keet weight (grams) 24.62
Source: Fani et al. (2004)
Hatching Egg Collection
Under normal temperature conditions hatching eggs should be collected four times a day. However, under extremes of heat (over about 28 oC) or cold (below about 5 oC) more frequent collection is recommended. High ambient temperature is one known cause of eggshell quality problems. During heat stress, feed intake is depressed and egg weight declines. Eggs should be stored in a temperature range of 15.5-18.5 oC and a relative humidity of 70-80%. If held for over 7 days before setting, hatchability declines progressively with increasing storage time. Other factors affecting hatchability are egg size, egg shape, shell quality and variations in incubator temperature as well as excessive shell porosity.
Shell quality from young breeder flocks is usually good and hatches are high, but as the birds continue through their laying year shell thickness and shell quality deteriorate and hatchability declines. Time egg is laid also has an effect on hatchability. For instance, hatching eggs laid early in the morning have poorer hatchability than those laid later in the day.
Eggs can be hatched either naturally or artificially. Egg handling prior to incubation is of paramount importance. Eggs should be collected at least twice daily and very dirty eggs discarded. As already mentioned the normal incubation period for guinea eggs is 26 to 28days and 24 to 25 days for the crossbreeds. The incubation method is the same as for turkey eggs.
Natural methods of incubation are generally used in small flocks. For larger flocks, incubators are more satisfactory. It is common to use chicken hens for hatching a small number of guinea eggs as they are more adaptable than guinea hens. Guinea hens usually are too wild to be set anywhere except in nests where they have become broody.
As soon as some of the guinea keets hatch and begin to move about, the guinea hen is likely to leave the nest, abandoning the eggs that are not hatched. These eggs may hatch if, while still warm, they are placed under another broody hen or in an incubator. Twelve to 15 eggs may be set under a guinea hen; 20 to 28 may be set under a large chicken hen. It is, however, necessary that hens are treated for lice before they are set. Forced-draft incubators should be operated at about 37.5 and 37.2oC and 57 to 58% humidity. During incubation, eggs must be turned regularly (minimum of three times) each day for the first24 days for pure guineas and 21 days for crossbreds.