Ear thermometer useful for monitoring chicken temperature

Newly hatched chicks are almost cold-blooded, so it is essential that they are kept in a warm environment to give them the best start in life.

But research has shown that the slightest variance outside the chicks’ comfortable temperature zone in the first few days of their life can have significant long-term effects.

“Good management during the first 48-72 hours of a chick’s life is essential to maximise immunity, performance and livability,” says David Scott, managing director at Lohmann GB. If the chicks get too hot or too cold, even for a short period of time, development of their immune system, thyroid and gastro-intestinal tract can be affected, leading to reduced feed conversion and growth, ill health and mortality.

Pullet rearers typically monitor air temperature in the poultry shed, and provide whole-house heating or gas brooders to keep the chicks warm. But air temperature – and even floor temperature – may not be the most important measures, says Mr Scott. It is the chicks’ body temperature that is critical.

“The ideal chick temperature is about 40.5C, taken using a modern human ear thermometer either rectally or in the naval. By monitoring the chicks’ body temperature carefully during the first few days of their life, producers can tailor their heating systems to provide the optimum environment.”

Humidity and airflow have a significant part to play, he adds. “Humidity is the heat transfer agent; too humid and the chicks will quickly get too hot; too dry and they will lose heat rapidly.” Relative humidity should be between 60% and 75% and airflow should be regulated to ensure sufficient heat circulation without wind chill.

Although costly, it is essential to thoroughly heat sheds to 31-32C before the chicks arrive, and for the first two days after delivery, as the floor temperature is vitally important to chick comfort, says Mr Scott. As the chicks grow they develop the ability to regulate their own temperature and need less heat to keep warm. Producers can, therefore, gradually lower the shed temperature by about 0.5C a day, until it reaches 21-23C after about 21 days.

But research has shown that extreme heat or cold stress for just one hour significantly reduces growth rates, with no compensatory gain in later life, says Mr Scott. Even slight variations outside the chicks’ comfort zone increase stress and reduce feed intake, often with long-term results.

“Getting it wrong can lead to chicks diverting vital energy to maintenance rather than growth and any reduction in growth rates in the first week can affect the overall performance of the flock.”

Rearers should, therefore, monitor chicks’ body temperature to get them off to the best possible start, taking a representative sample from around the house twice a day for the first five days, he adds. Rectal temperatures of over 41.1C are too high, with the chicks likely to display stress signs like panting, chirping, and spreading away from heat sources. Cold chicks below 40C will have cold feet and will be less active, huddling around heat sources.

Those measuring 40C may not display signs of stress, but will be struggling to maintain body temperature and, therefore, diverting energy away from growth and organ development. “This is the most important group to test for. Most rearers will be aware of stressed chicks, but unaware of this group of chicks that, left alone, may struggle to achieve the required bodyweight gain,” says Mr Scott.

The ideal chick temperature is 40-40.8C; chicks will be spread out, eating and drinking, with warm feet. “What really matters is how the chicks look, not just what your thermostat says. You have to respond to the conditions, depending on the environment and time of year.”

Chicks from younger breeding flocks (below 35 weeks old) are more susceptible to temperature changes, and may not display such obvious signs of stress, he adds. “Chicks from different sources will have different requirements, and a useful way to ensure that their needs are met is to measure their body temperature and react accordingly. The first 48 hours go by quickly, but are essential to the future development of your flock.”

How does the ear thermometer work?

The temperature sensor in the ear thermometer is sensitive to subtle changes in infrared emission. One common sensor is the thermopile, which can be accurate to a 10th of a degree.
To measures the temperature of a chick, take the thermometer and hold it against the chick’s naval or rectum. The thermopile then measures the infrared emissions from the bird and this is converted into a temperature, as displayed on an LCD.

Key points

• Chicks cannot regulate temperature until two weeks old
  
• Slight temperature fluctuations can have significant long-term impacts
  
• Body temperature is key to success
  
• Consider air, water, floor and food temperature, as well as humidity and airflow