That discovered researcher Ingrid de Jong of Wageningen Livestock Research. ‘The housing in the first weeks of a chick’s life has a big effect on its health and behaviour, and consequently on well-being,’ says De Jong.
On commercial poultry farms, chicks spend 23 hours a day in the light for the first couple of days to make sure they get enough to eat and drink. ‘It’s hard for them to get any rest then.’ De Jong and her colleagues investigated the effect of what they call a ‘dark brooder’ in the barn. ‘It offers a dark, warm place for the chicks to crawl under and rest, a kind of substitute mother hen.’
Chicks that have access to a ‘dark brooder’ are more symmetrical
De Jong discovered that chicks with access to a dark brooder were more symmetrical, meaning for example there was no difference in leg length. De Jong: ‘Asymmetry is a sign of stress. This therefore seems to indicate indirectly that the chicks are less stressed.’
It was also noticeable that chicks with access to a dark brooder had a less varied microbiome — the micro-organisms such as bacteria and fungi in the guts — at the age of two weeks, but they had more ‘good’ gut bacteria. De Jong: ‘A varied microbiome is associated with less stress and therefore potentially better well-being, but surprisingly our results point in the opposite direction.’
It is known that the microbiome is important for the immune system, explains the researcher. ‘In humans the link between the microbiome and behaviour has been studied in great detail, but not in chickens. We want to do that in future.’