Dr Oscar Blanco (BVSc, PhD)

This article is part of a series. Remember to read Part 2:Emulating mother hen

A comfortable chicken is a profitable chicken which guarantees more money in the farmer’s pocket. Therefore it is of utmost importance to understand the science behind happy chickens. Over the next three months we shall investigate this important matter.

This series consists of three articles, aimed at understanding why we need to brood small chicks and what the consequences of suboptimal brooding are. It should be made clear that these documents do not intend to be a guideline for brooding, so the reader is encouraged to contact his/her day-old-chick supplier to get practical recommendations on the matter.

Giving the chicks a warm environment

Brooding is, arguably, the most crucial stage in the life of broiler chickens and comprises the first 2 weeks of the chicken’s life. Failure to achieve the desired environmental conditions during this time results in developmental and health problems that affect the birds not only during the brooding period, but it may also compromise the future performance and liveability of the birds.

Historically, Zambian winters are short and temperate; however, 2016 has been particularly cold. These conditions have clearly shown out the shortcomings in brooding techniques. This resulted in many farmers having experienced an increasing feed conversion ratio, longer finishing times and/or higher mortality towards the end of the production cycle (mainly due to ascites). This situation had a negative impact on the profitability of those enterprises, resulting sometimes in net losses.

Why do we need to brood our birds?

Fully grown broilers are able to control their body temperature, maintaining it in a very narrow range (between 40,5 °C to 43 °C) when they are exposed to a wide range of ambient temperatures. This regulation is achieved by using a few mechanisms that, when working together, result in a net increase or decrease of heat loss to the environment.

The basic idea is as follows: the more heat a bird retains in its body, the higher its body temperature will be; equally, the more heat the bird loses, the lower its body temperature will drop.

When the bird is in a cold environment, it naturally tends to lose heat, so it uses those regulatory mechanisms mentioned above in order to produce more heat in its body and to decrease the heat loss to the environment.

Conversely, when the mature bird is in a warm environment, those mechanisms are tuned into “heat-loss mode” to avoid its body temperature to escalate, for example the bird begins to pant.

These mechanisms are used at a cost, for example a higher need of feed energy during winter. (This article is not directly concerned with such costs, so they will not be further discussed.)

However, in the first two weeks of life, chickens are incapable of such fine-tuning. Furthermore, since their feather coats do not offer good insulation, and also due to their small body size, they tend to lose heat at a very high rate. In order to counteract these initial regulatory limitations, the mother hen gives her hatchlings insulation and heat by covering them under her wings. Furthermore, the hen procures food for her chicks and teaches them how to eat.

In intensive broiler production, the incubator has replaced the broody hen before hatching. After hatching, it is necessary to emulate what the hen does by keeping the chicks at appropriate temperatures, with plenty of food and water at their disposal.

Moreover, we need to make sure chicks find the feed and the water during the first day, and help them to do so if needed.

As mentioned above, failure to provide proper brooding conditions results in increased mortalities during the first two weeks, as well as in developmental problems that will affect the birds towards the end of the production cycle.

Next month we will look at how a farmer can emulate the mother hen in his pens for optimum results.