New research out of the University of Alberta says chicken breasts are 80 per cent larger and hens have nearly doubled in weight over the last six decades. 

Martin Zuidhof, a poultry science teacher at the University of Alberta and researcher behind the study, spoke on the Calgary Eyeopener this morning about why chickens on average have quadrupled in size since the 1950s.

"In the '40s there was a contest — the chicken of tomorrow contest — that really got the whole idea of breeding chickens for meat ... [and] gave it legs so to speak," said Zuidhof.

"The industry went after the fastest growing chickens, the most efficient chickens and now rather than chicken meat being a byproduct of the egg industry, we have chickens that are grown specifically for meat. And they grow at a rapid rate and they're very efficient."

Zuidhof says his study focused on how the genetics of chickens have changed.

"When we did this study we used 1957, 1978 and 2005 lines of chicken — commercial unselected lines — and we fed them exactly the same things, so we did not provide hormones," he said. 

Selective breeding

"The only difference that was part of our study treatments was the genetics."

Zuidhof makes it clear the changes are not because of genetic manipulation but just selective breeding, which is very effective.

"They have a very short generation time and they have a lot of progeny ...  you can implement that genetic change much more quickly than cattle for example."

"The research I do at the University of Alberta is all about producing food efficiently and sustainably," said Zuidhof.

"With half the feed we can produce chickens now compared to what they did 50 years ago."

With some population estimates suggesting there may be 12 billion people in the world by the year 2100, Zuidhof feels efficiency will be the key to sustainable food production in the future.