Jo Ann Chew. Photo by Gord Waldner.

In the right light

Graduate student aims to improve housing conditions for laying hens.

By Kathy Fitzpatrick

As egg farmers of Canada switch from conventional cages to alternative housing systems for laying hens, Jo Ann Chew is working to help pinpoint optimal conditions.

A graduate student in the Department of Animal and Poultry Science at the University of Saskatchewan’s (USask) College of Agriculture and Bioresources, Chew is trying to determine the most appropriate light levels inside chicken barns.

Low light levels keep chickens calm but they may not be able to see well enough to navigate successfully through their complex living space. Brighter light makes them more fearful, aggressive and flighty.

“My project is to find what the right balance is,” Chew said of the research for her master’s thesis.

The right balance is especially important in alternative housing, such as free run systems or enriched cages with perches and nest boxes. Grouping chickens together in larger numbers tends to increase feather pecking which can lead to cannibalism, Chew says. And, with more space to fly around, there is more chance of the birds crashing and breaking bones.

The current industry standard for minimum light levels is five lux (a measurement of illuminance) in conventional housing, 10 lux in alternative housing.

To put that into perspective, zero lux is total darkness while 500-800 lux would be typical office or classroom lighting, Chew explains.


However, she says more study on the current standard of five and 10 lux is needed.

To that end, she is testing the effects of 10 lux, 30 lux and 50 lux on behaviour, stress and fear levels, and bone health. Her subjects are two strains of laying hens, Lohmann LSL-Lite and Lohmann Brown-Lite, from the time they’re hatched to 16 weeks of age. They’re housed in floor pens equipped with perches, ramps, feeders and drinkers.

Chew has ceiling-mounted infrared cameras taking 24-hour footage four times throughout her research trial. During play back, she pauses every 20 minutes and notes what each bird is doing at that exact time, a technique called instantaneous scan sampling. She also watches an entire 24-hour period and counts the birds’ successes and failures in navigating their environment (behaviour sampling).

To check stress levels, Chew takes blood samples from the wing vein to measure heterophil-lymphocyte ratios “which is a measure used to determine stress levels in birds.”

And to gauge fear levels, she places a novel object in the pen and times how long it takes for up to three different birds to peck at it.

To assess bone health, Chew palpates keel bones searching for deviations or fractures, and will dissect some birds at the end of the trial. She will put their tibias through a machine to measure the bone breaking strength.

In all, Chew is conducting two trials over a two-year period. Sometime later this year, she expects to have all of her data and will begin to analyze it.

Her work is part of a larger project on the transition to alternative housing, involving researchers at the University of Guelph and McGill University.

“It’s going to benefit possibly the (whole) of Canada, and maybe even worldwide too … It’s very exciting,” Chew said.

Poultry science may seem an unlikely career choice for a Malaysian-born city kid. But looking back, it’s clear how it fell into place.

Growing up, Chew had always loved animals. While in high school she and her family emigrated to Canada, arriving in Edmonton.

Her mother, an IT trainer, observed how popular pets are in Canada, and suggested Chew go into veterinary medicine. Her father, a project manager in hotel construction, saw opportunities in farming.

“He said one day the world will go hungry … and they’re going to need someone to feed them,” she recalled.

So she steered a middle path, entering the University of Alberta to study Animal Health, majoring in Food Animals.

Chew also remembers seeing news reports of abused farm animals, and thinking “If I get into that industry I can change the game.”

She said she has since learned from her professors that farmers love their animals and treat them well, and so her approach has shifted from reformer to facilitator in the humane care of livestock.

Two professors in particular inspired her to pursue poultry science and research in that field. Independent studies under the supervision of Drs. Martin Zuidhof and Frank Robinson from the University of Alberta gave her the first glimpse of what it’s like to engage in research.

“I just think it’s so cool finding out the way science plays a role in bird management” by bridging a knowledge gap, Chew said.

She also enjoys the teamwork. 

As she neared the end of her undergrad studies, Robinson urged her to pursue a Master’s degree. He recommended she work with Dr. Karen Schwean-Lardner (PhD) at USask.  Schwean-Lardner secured funding for the research project Chew is now completing and became her thesis supervisor.

Chew said one of the main things Schwean-Lardner has taught her is to “think like a scientist,” critically evaluating whatever she sees or hears.

After this, Chew remains open to either working in industry or staying in research. Either way, she looks forward to learning more about production and management—for the benefit of animals, producers and consumers alike.

 Story from Agknowledge, Fall 2019.