Stress in animals is a complex subject! Find out more about the causes of stress in game birds and ways you can minimise stressful situations. Helping to identify signs of stress can really impact the welfare of your birds which could be resulting in considerable hidden costs on your site.

What is stress in birds?

Gamebirds don’t pay bills, get stuck in traffic jams, or worry about their BMI, but they do have predators, suffer after sudden changes in food, and struggle with extreme weather. All of these cause stress and put pressure on our birds’ minds, behaviours, and bodies. Birds experience the world differently from humans, have different concerns, and don’t express emotions in ways we can easily interpret. Trying to define and understand stress in animals is difficult. Stress could be viewed as unexpected changes and pressures placed on the animal which it must cope with or resolve.

The types of stress to consider in gamebirds include psychological (the mind and behaviour), and physiological (the functions of the body). Psychological stresses include being chased by a predator, feather pecking and being bullied by other birds. Physiological stresses include changes in feed, being too hot or cold, or suffering from a disease. Many stressful events include overlapping physiological and psychological stress factors, such as being caught up, crated, and moved to a new site where different feed is being given.

How does stress effect birds?

Some stress factors only last for a short time, often by the birds moving away from the cause of the stress, such as predators, heaters, rain, or bullying birds. If these stressors are not frequently repeated, they may have little impact on the overall health of the birds.

However, longer term or repeated stressors may have severe consequences. These might include not being able to get away from bullies, temperature extremes and prolonged stressful events, such as bitting, crating and transport, or a change in feed.

Stress has many effects on the body. One is frequently called the “flight-or-fight response”, which helps the birds move away from the cause of the stress, so they can get to somewhere safer. However, prolonged stress negatively effects the digestive system, growth, and the immune system. This is due to hormones, such as cortisol. The specifics of these hormones are extremely complex, but when experiencing stress, the levels of these hormones increase and help the bird survive by prioritising survival mechanisms over other bodily functions. For example, cortisol prevents the digestive system from absorbing vital nutrients, causes muscle breakdown to generate extra energy, and prevents the release of chemicals needed for immune responses. This in turn reduces growth, the ability to digest food effectively which helps to maintain a healthy gut flora and the ability to control infection, all of which increases the risk of disease.

How can I tell if my gamebirds are stressed?

Often you can’t. Gamebirds are prey species. They try to never show stress, pain, or disease as this might make them obvious targets for predators or even each other. Stress can be exhibited as unnatural or unusual behaviours, such as feather pecking, decreased weight gain, decreased food or water consumption, and increased flightiness.

Some stress response behaviours, such as flying, are expected and desired in gamebirds. They have natural, wild behaviours which we want to retain, such as running and flying. We don’t want our game farms to breed out these traits and produce docile, domesticated gamebirds, which would not survive in the wild.

It is impossible to get an absolute balance of these traits, but we can work to limit the stress factors imposed on our birds through good management and welfare, as well as providing them support via appropriate supplements and enrichment.

How can we control stress?

You can’t prevent stress entirely, but you can control and limit it by appropriately managing stress factors and providing supplements to reduce stress.

A few examples include:

  • Appropriate stocking densities – in 2020 many sites decreased their stocking densities. This is believed to be the reason we saw a national decrease in the level of Mycoplasma cases.
  • Gut health management – Good, stable, gut bacteria will promote growth and immune function in birds, as well as helping them cope with changes in feed. Probiotics help establish good gut flora, Water sanitisers and acidifiers reduce the risk of disruption to the gut flora, and prebiotic supplements will help the gut flora to grow.
  • Good bitting training – If bitting is necessary it should be quick and effective. Training staff to do this properly will reduce the stress on the birds.
  • Electrolytes and magnesium supplements – Excellent for helping birds control their stress levels. These should be given 1-2 days before stressful events, such as bitting and transport, or during stressful events, such as hot days and feed changes.

Stress in animals is complex and this article is simply an introduction to a subject which could be resulting in considerable hidden costs on your site.

For more advice on stress in your birds and how to control it, contact your vet.

Will Ingham – Poultry Health Services