Tag Archives: self-sufficiency

Helping your hens survive the heat

The Chook Chronicles: Heat Stress in Backyard Hens

Although the weather seems not as bad as it was last summer, average temperatures are still 1 – 2°C higher than the long term average, and heat waves are tending to be hotter and longer. Tragically, quite a few friends and neighbours from Guildford and surrounding suburbs have recounted the terrible upset of losing hens to heat stress.

Summer’s not over yet, so now is a good time to review what you can do to prevent deaths due to heat stroke, and to reduce heat stress in your backyard hens.

The body temperature of chickens is higher and more variable than that of mammals; in adult hens it ranges from 40.6 – 41.7°C. Smaller breeds tend to have a higher body temperature than larger ones, probably due to metabolic rate. Activity increases body temperature, and chickens that are growing or producing a lot of eggs will also have a higher average body temperature.

A hen’s high average body temperature makes it easier to lose heat into the surrounding air, but like humans, this happens most easily when air temperature is well below body temperature.

The ideal air temperature range for chickens at which their body functions best (the ‘thermal neutral zone’) is 18 – 24°C! Hens therefore begin to experience a degree of heat stress above 24°C. Just like people though, the temperature range that chooks can stand depends on the length of exposure, and what protection they have.

Birds do not have sweat glands, so they pant to evaporate moisture for cooling, and to draw into their air sacs deep in the body to cool it. Hens will start to pant above 32°C and above 50% relative humidity. However, panting for evaporative cooling loses effectiveness above 70% humidity, greatly reducing birds’ ability to tolerate heat. The lethal upper limit for body temperature for chickens is 45 – 47°C. Chickens are at risk of death from heat prostration at air temperatures above 38°C.

Clearly, chooks are most vulnerable to heat stress during the following weather conditions:

  • Heat waves: especially when high temperatures persist for more than 3 days
  • Peak daytime temperature reaches or exceeds 35°C
  • Heat fails to dissipate overnight. Like people, hens can recover well if night-time temperatures drop back down to or near their ‘neutral zone’ (ie below about 26°C)
  • Periods of high humidity, e.g. common in late February in WA
  • Chooks that are broody or at peak of egg laying are particularly vulnerable
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Both hens below are panting – breathing through open beak instead of nostrils. Small hens such as the bantam hen on the left have a higher body temperature than larger hens, and are thus more susceptible to heat stress. The Isa Brown hen on the right has some feather loss, which likely helps to release body heat.

Ways to minimize heat stress in backyard laying hens

  • Fresh drinking water must be freely available at all times. Hens will drink twice as much at 38°C compared to 27°C. This can be as much as 400 – 500mL per average sized laying hen per day when it’s hot. The longer hens are exposed to high temperatures, the more they will drink (i.e. they drink more on the last day of a heat wave than the first day). Hens that are at their peak of lay will drink 50% more than average egg layers.
  • On very hot days, offering chilled water is beneficial – well below 28°C (e.g. add ice cubes or use an insulated container). Hens will drink more and lose heat more easily
  • Access to full shade – natural or artificial. Shade will also reduce reflected sunlight and glare, as long as trees, branches and other types of shade are situated in a way that does not interfere with air flow
  • Ventilation: Unrestricted or unobstructed air flow helps reduce the heat load through natural (location, pen construction) or artificial (fan) means
  • Evaporative cooling, e.g. wet hessian, jungle fogger, mister, sprinkler on the roof or in the pen. Solar misters, sprinklers and fans are now quite affordable and may be set to operate on a timer at peak times of the day
  • Feed at night when heat produced through digestion will be less. On very hot days, avoid feeding for 6 – 8 hours before the hottest part of the day
  • Ensure that the hen house is well insulated. Metal enclosures or a metal roof can greatly magnify and radiate heat
  • Heat stress is additive with other sources of stress such as parasites, social stress from insufficient space, broodiness, introduction of new hens, etc. Always take weather into account when managing these other potentially stressful factors
  • If you have a broody hen that is not actually sitting on eggs when a heat wave is expected, consider taking measures to discourage broodiness at this time. If hens are incubating eggs, make sure they have access to water at all times and are located in a deeply shaded area.
  • If no one is at home on very hot days, consider inviting a neighbour to check on your hens during the hottest part of the day. Checking shade and water, providing a sprinkler briefly or adding ice cubes to water may mean the difference between life and death.
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Heat stressed rooster panting (breathing fast with an open beak). Note the very bad infestation of stickfast mites all over his comb and wattles (black).

If you would like to learn a bit more about chickens and hot weather, search for ‘heat stress’ on The Poultry Site

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Hot off the presses: TTG olive oil

Recently, a small group of TTG members ventured forth to gather a very special type of seasonal produce: olives. Image

The sandy soils and Mediterranean climate of the Perth region create a perfect growing environment for these plants, and in the space of a few short hours the foraging party was able to accumulate quite an impressive haul: 140 kilos! Image

The next step was to deliver the bounty to Jumanga Olives in Carabooda for processing. It seems we were not the only ones who were keen on obtaining some fresh oil—there was quite a queue of olives! Image

We were asked to return for our oil 3 days later. Our pickings yielded 23 lovely litres of liquid gold which then needed to settle for a further 3-4 weeks.  Different varieties will each produce a unique blend, and it is suggested to include up to 30% green fruit in order to optimise flavour. Image

It is very satisfying that a few hours of easy work with friends can yield such productive results. There must be many more opportunities like this which are “ripe for the picking”, and if we can work together then we can also share the fruits of our labours.

Planting out a spring garden at Rebecca and Andy’s place

This month the Guildford Kitchen Gardeners are getting our hands dirty.  Rebecca and Andy have been wanting a vegie garden for a while, and have generously agreed to share putting it together with us.  If you’ve been wanting to set up a garden and haven’t known where to start, this is a great way to learn.

They’ve done all the hard work, so we’ll come in and help them finish it off, followed by afternoon tea, of course.

Please bring:  your gardening gloves and gardening tools, something for the sharing table if you have excess in your garden, some homemade yumminess to share for afternoon tea.  (these last two are not obligatory – if you’d like to bring something to share, please do but don’t feel obliged, we will have plenty).  Also, if you have a camp chair, you might want to have a sit down after all the hard work.

Here’s how it will work:

1.30:   Arrive and reacquaint with everyone
2pm:  Let’s get to work!  Rebecca has plans of what’s to be planted where, as well as seeds and seedlings.  We’ll be moving some soil, then planting seeds and seedlings.  There are also a couple of trees needing new homes.  Rebecca will have seeds and vegie seedlings, but would love donations if anyone has herb seedlings looking for a new home.
3.30:  Time for a well earned cuppa, biccie and a chat.
4pm: Done!

As we go, we’ll discuss soil health, companion planting, timing of planting various species, recipes and whatever else is of interest.

Please RSVP for address, to guildfordkitchengardeners@gmail.com.