The evolution of the species has a genetic origin and is influenced by its environment. Broodiness is usually presented as a normal hens’ physiological state, in which they stop laying eggs and focus on their incubation. In nature, it constitutes a normal and indispensable behaviour for the reproduction and conservation of its species.

However, in modern days’ bird breeding broodiness is usually seen as something negative that affects production, and not as a normal and natural way to conserve the species. This is one of the reasons why artificial incubation has gradually been introduced. This phenomenon has pushed chicken breeders to reduce its appearance through genetic selection, to the point that broodiness has become less frequent in recent years.

Identifying broodiness’ features

Physiologically, broody hens are recognized for their resistance to leave the nesting box, bristling feathers, loss of appetite, increased pecking and for emitting a hoarse sound. Broodiness consequences in the poultry industry directly affect egg fertility rates and production, since hens tend to reject males.

Broodiness in industrial coops is often caused by mismanagement:

• excessive animal density
• insufficient number of feeders and drinkers
• inadequate ventilation
• poor luminous intensity or lack of lighting uniformity
• excessive permanence of eggs in the nest boxes
• insufficient bird weight and
• excessive batch heterogeneity
• nesting boxes remain open at nigh
• excessive number of nests
• lack or excess of active roosters
• presence of a subclinical pathological process

Although genetics may play an important role as it is a normal bird physiological process.

Possible causes of broodiness

This phenomenon is caused by prolactin hormones secreted in the anterior lobe of the pituitary gland. It is highly influenced by light intensity and, to some extent, its greater or lesser presence will depend on climatology; a warm or temperate environment.

Broodiness manifests more in some chicken breeds than others, so it is hereditary. Although very little is known today about how this character is inherited. Some cross-breeding studies show the hypothesis of complementary genes by genes linked to chicken gender and others favoured by maternal inheritance.

Need of preservation of different chicken breeds

In this sense, it would be necessary that poultry farming authorities of different countries, geneticists and universities made the commitment to preserve different chicken breeds and, in doing so, avoiding the loss of genes that may be useful to keep developing new chicken lines in the future. Poultry is, after all, of extreme importance as a source of protein for human consumption.

Hence, the need to establish different breeds’ genetic profiles is key to avoid excessive dependence on just a few monopolistic breeding farms. Often, the negative effects before the outbreak a sanitary-type pandemic are left out. A ban on animal -and animal products- exportation from one country to another due to a disease outbreak may have negative consequences not only production-wise, but for price stability and the supply to the food market.