Managing Heat Stress in Laying Hens

Tips on how to keep hens consuming the water and nutrients necessary for egg production during hot, humid weather  Photo: Shutterstock

As temperatures and humidity levels increase in the summer, it is important to understand how heat stress can impact your laying hen flock.  Signs of heat stress in a hen are raising and spreading of her wings, panting, and trying to increase contact time with cool surfaces, trying to cool herself down.  While heat stress is typically not severe enough to cause mortality in a flock, even minor heat stress will have a negative impact on the flock and the producer’s bottom line.  Recognizing the signs of heat stress and being able to effectively manage your laying hens will help alleviate the negative effects of heat stress in your flock.

Effects of Heat Stress 

The effects of heat stress in laying hens include a decline in feed consumption, as well as a reduction in egg production, egg size, and shell quality.  When this happens, consider increasing the protein level of the feed.  This will ensure the hen is getting enough protein to support her dietary needs, egg production and egg size.  Reconsider the texture of the feed for the hen, as a coarse textured feed will help increase consumption. 

The hen will pant to cool off and as she does this, carbon dioxide (CO₂) is lost from the blood.  With reduced carbon dioxide levels in the blood, the blood pH rises.  This change in the blood gas levels reduces the amount of calcium carried to the hen’s uterus for shell formation.  Boosting the level of calcium in the feed will not correct the shell quality issue, as it is caused by blood gas levels.  Adding electrolytes to feed or water will also stimulate water intake and help balance blood electrolyte and gas levels. The use of bicarbonate in the feed may also give dditional benefits.

Poultry Specialist Kristen Thompson-Dow writes about how understanding how to manage feed, water and the barn environment can help alleviate the ill effects of heat stress.

Feed and Water Consumption

The hens feed consumption is very important as the laying hens will not feel like eating through the heat of the day (10 am-4 pm).  To ensure she is eating enough to support her egg production, review how the feeding times are set up in your facility.  Monitoring the depth of feed in the trough, ensuring that feeders are running early in the morning and evening (as these are cooler times of the day), and adding stirs throughout the day will encourage feed intake.   A midnight feeding added in the evening can also aid in increasing feed consumption at a cooler time in the barn.  Water consumption is of particular importance during heat stress, as this helps cool the hen down.  Make sure the water lines are flushed regularly to ensure fresh, cool  (60-65°F or 15.5-18.5°C) water is available, as well as ensuring the water pressure and volume is adequate to deliver water to all of the barn.  Tracking the temperatures inside and outside of the barn is also a significant aid in managing the effects of heat stress.  

Monitoring the barn environment and staying on top of barn maintenance plays a major role in reducing the economic challenges associated with severe heat stress.  Ventilation plays a key role for helping the birds through high temperatures and humidity.  Lowering the set points in the barn to maximize air activity will move this hot, humid air out of the barn and replace it with fresher, cooler air which will greatly benefit the hens.  Regular maintenance on your ventilation system, such as inspecting fan belts, fan blades, covers and air inlets (air inlets on the outside of the barn should be cleaned or washed at least twice a year) will verify they are clean and operating correctly.  Another option is using water misters at air inlets as this will help cool the air coming into the barn.  Finally, verify all alarm systems are working and set up correctly as this system is a significant part of ensuring that your laying hens are not heat stressed during the summer months.

Understanding how to manage feed, water and the barn environment will help alleviate the ill effects of heat stress, keeping your laying hens consuming the water and nutrients required to support egg production and quality during the hot, humid summer months and diminish a negative economic outcome.