10 simple ways to recognise heat exhaustion in chickens.

Why it's potentially fatal, how to spot it in time and what to do.

Knowing how to recognise heat exhaustion could save your chickens' lives.

Both heat exhaustion and heat stroke can develop surprisingly quickly, and can be fatal if they're not recognised and treated promptly.

In this article, you'll learn how to recognise the warning signs of heat exhaustion, understand why it happens, and discover what you can do to help your flock recover safely.

If your chickens are already showing signs of severe heat stress, use the links below to jump straight to the emergency advice.

Every minute matters.

Why is recognising heat exhaustion important?

A chicken's normal body temperature^(1, 3) is between 40ºC and 41ºC (104ºF and 107ºF). But unlike mammals they don't have sweat glands, so they have limited ways to cool themselves down.

Why does it happen?

Some breeds cope with hot weather than others⁽²⁾. 

Breeds that originated in cooler, temperate climates often struggle more in high temperatures, so it's worth considering your local climate when choosing a flock.

• Breeds that come from cooler, more temperate climates tend to struggle more in high temperatures, so it's always worth considering climate when choosing your flock.

• Older chickens may cope well if temperatures rise gradually, but sudden heatwaves can catch them out.
• Heavy breeds are also more vulnerable because they retain more body heat. Broilers, bred for meat production, are particularly susceptible to heat exhaustion, and research shows that broiler chicks between six and eight weeks of age are at even greater risk than adults.(4)That flows a little more naturally.

• Heavy breeds are also more vulnerable because they retain more body heat. Broilers, bred for meat production, are particularly susceptible to heat exhaustion, and research shows that broiler chicks (between 6 and 8 weeks old) are at even greater risk than adults⁽⁴⁾.

How to tell if your flock is suffering from heat exhaustion.

The following ten signs are listed in roughly the order they usually appear, from the earliest warning signs to the most severe symptoms.

Not every chicken will show every sign, but the further down the list your bird has progressed, the more urgent the situation becomes.

Heat exhaustion: early warning signs.

1.  Panting

The first and most obvious sign of heat stress.

If chickens can't lose body heat quickly enough, their internal temperature keeps on rising. The same feathers that keep them warm in the winter also trap heat in the summer. 

Since chickens don't have sweat glands, they rely on evaporation through their respiratory system. In other words, they pant.

A panting chicken is usually easy to recognise. She'll stand (or sit) with her beak open, breathing out moist air, often silently rather than making the usual chicken noises.

2.  Rapid breathing. 

Closely related to panting, this happens when humidity levels are high. 

Because the air she's breathing out is already full of moisture, it's hard to expel. To compensate, her breathing increases from a normal 20 breaths per minute to as much as 240⁽³⁾.

That's a huge jump, and it creates a vicious cycle: faster breathing uses more energy, which produces more heat.

That's why heat stress can worsen surprisingly quickly if chickens aren't helped to cool down.

3.  Loss of electrolytes and dehydration. 

Unlike panting or outstretched wings, you can't see this happening.

As chickens lose water, they also lose electrolytes. These are the essential minerals that help their muscles, nerves and other body systems work properly.

Think of electrolytes as a chicken-friendly version of Gatorade, but without the sugar and colouring.

If those losses aren't replaced, dehydration and electrolyte imbalance can contribute to serious health problems, including poor immune function and respiratory problems.

It also depletes calcium stores, which can lead to soft-shelled eggs (see symptom 8 below).

That's why I always keep a bottle of electrolyte powder in my chicken first-aid kit. During very hot weather, or if I notice early signs of heat stress, I add it to their drinking water according to the instructions.

That's why I always keep a bottle of electrolyte powder in my chicken first aid kit. During very hot weather, or when I notice the early signs of heat stress, I add it to their drinking water.

But you can easily make your own if you have none in stock and need it urgently.

4.  Wings held away from the body. 

This is the chicken's way of trying to cool down: by exposing more skin to cooler air, instead of trapping heat under the feathers.

You'll often notice this while hens are dust bathing. In mild heat they simply hold their wings away from their bodies. As temperatures rise, one or both wings may hang lower until they almost touch the ground.

Heat exhaustion: critical stages.

If your chickens have progressed beyond the early warning signs above, it's time to act quickly. The following symptoms suggest heat stress is becoming much more serious.

5.  Stops eating and drinks much more water.

Panting makes eating difficult. When a chicken is concentrating on cooling herself down, feeding becomes much less of a priority.

Chickens naturally eat less in hot weather, but if feed intake drops dramatically it's worth paying attention. Watch for individuals who seem to be missing mealtimes altogether.

When it comes to drinking water, overheated chickens can drink four to five times as much as usual. Make sure your waterers are topped up frequently – they may empty more often than you expect. 

6.  Diarrhoea. 

Loose droppings are often a natural consequence of drinking much more water than usual.

Why does this matter? Because more liquid loss equals yet more electrolyte loss, which weakens the immune system and leaves them more vulnerable, particularly if hot weather continues.

7. The chicken becomes listless, droopy and disinterested.

It's not surprising really – think about how you feel in a heatwave.

By this stage, your chickens are becoming increasingly dehydrated. They've lost electrolytes, they're eating very little and their bodies are working hard just to keep cool.

As a result, they'll often seem quiet, sluggish and uninterested in what's happening around them.

8.  Egg production drops, and shells become thin or soft.

By now, your chicken's body is under considerable stress. She's eating less, panting more and using precious energy simply to stay alive.

Calcium is diverted away from egg production, so laying often slows down. Eggs that are laid may have thin or soft shells.

And soft shelled eggs cause their own problems including egg binding or even internal breakages.

Never seen a soft-shelled egg? 

Here's a short video from my friend, Tim Daniels of PoultryKeeper.com, showing exactly what they look like.

Heat exhaustion: emergency stage.

9.  Staggering, disorientation and seizures. 

At this point, a chicken is likely to be very severely dehydrated. Immediate action is essential if you're to have any hope of saving her. 

Her body is starting to shut down. Without immediate cooling and supportive care, this stage is often fatal.

10. Collapse of system and death.

By this stage, severe dehydration and electrolyte imbalance have overwhelmed the body's ability to function normally. Without veterinary intervention, survival is, sadly, very unlikely.

The goal, of course, is to recognise and treat symptoms long before they reach this point.

Can heat exhaustion in chickens be prevented?

In most cases, yes.

The best treatment is prevention. By providing plenty of fresh water, shade, good ventilation and cooling treats before temperatures become dangerous, you can greatly reduce the risk of heat exhaustion.

I've put together a complete guide with six simple, practical steps to help your flock stay safe during hot weather.

Other summer problems with chickens?

Summer time can bring other problems with our flocks. These articles will help you sort some of them out. Just click on the pics.

Sources.

I make every effort to provide readers of my site with information which has been confirmed by scientific, peer-reviewed research, particularly where health issues are concerned.

For this article, some of the most helpful sources are:

1. Borges, S.A., et al: 'Physiological responses of broiler chickens to heat stress and dietary electrolyte balance'.  Pub.  Oxford Journal of Poultry Science, 2004.

2. Gail Damerow: The Chicken Encycolpaedia: an Illustrated Reference.

3. Rural Chemical Industries Ltd: 'Thermoregulation in poultry'. Pub. Heatstress in Livestock.

4. Tirawattanawanich, C., et al: 'The effects of tropical environmental conditions on the stress and immune responses of commercial broilers, Thai indigenous chickens, and crossbred chickens'.  Pub. The Journal of Applied Poultry Research, 2011.