Why did the chicken cross the pen? No, seriously. That’s a legitimate scientific question. The way chickens move through a pen may tell us a lot about whether or not they’re feeling well and how many opportunities they have to spread illnesses. Now scientists are studying how chicken locomotion can reveal disease—knowledge that could help farmers do a better job of heading off certain kinds of outbreaks. 

As he and his colleagues recently recounted in the journal Mathematical Methods in the Applied Sciences, Arni S.R. Srinivasa Rao, a mathematical modeler and associate professor at Georgia’s Augusta University, has spent years developing mathematical models that could aid in the understanding of how Avian flu spreads.

Recently, he teamed up with collaborators Fiona Tomley and Damer Blake, from the Royal Veterinary College at the University of London, to learn about outbreaks of Eimeria, a parasite that spreads easily among chickens and other farm animals, causing diarrhea, weakness, and weight loss. The pathogen costs the poultry industry billions of dollars each year.

“The livelihood of farmers depends on their poultry, so it’s a big loss if we’re not using technology to support them,” said Rao.

One day while observing a group of chickens in their pen, Rao had an idea: What might be learned about the spread of Eimeria by documenting the routes chickens take as they go about their daily business—mainly eating, drinking, scratching, pecking, and defecating—and plugging that data into mathematical models?

Rao and his collaborators observed chicken pens in India and in England. He recorded the chickens’ routes and the amount of time they spent eating and drinking, walking and standing around, and where they pooped and pecked.

The next step involved plotting on a grid each chicken’s movements, and multiplying that by the total number of chickens to find out how often they crossed each other’s paths, and hence had opportunity to spread disease.

He also analyzed individual chickens’ movements to look for deviations in their idiosyncratic patterns, which might indicate illness.

“What we see is that the distance covered by a sick chicken is substantially less than for a healthy chicken,” said Rao. “Infected chickens become so sick that it’s difficult for them to move, while healthy chickens frequently jump around and move to different parts of the pen.”  

Plotted on the grid, the sick chickens’ paths appear as a single line between, say, the water and the roost, while healthy chickens produce multiple lines that cover the entire space of the grid.

The next step for the team is to use animation software and generate models that can help predict the movement of sick and healthy chickens within a particular group.

Rao would eventually like to see farmers themselves use animation software to translate video of their flocks into visual patterns and models that can help identify sick birds in as little as a day—something that isn't so easy on large poultry farms.

These models would allow farmers to more quickly isolate a sick chicken, reducing treatment costs and slowing the spread of disease. Rao believes similar models could also be adapted for other farm animals.