Canadian Poultry Magazine

CPRC Update: November 08

By CPRC   

Features Business & Policy Consumer Issues

Managing Broiler Breeders

The Canadian Poultry Research Council (CPRC) provides funding for research projects under a number of themes. Below are summaries of the final reports for two of these projects:

Managing broiler breeders
The laying performance of commercial broiler breeder chickens can vary widely. Careful management decisions are required, especially during sexual maturation, to maximize egg production. Drs. Frank Robinson and Robert Renema, and their team at the University of Alberta have undertaken a large research program on broiler breeder physiology and are working towards a better understanding of the impact of various management decisions on breeder performance.

Protein intake
One aspect being examined within this program is the interaction between protein intake and reproductive efficiency. An experiment was set up during which pullets were fed either a standard breeder ration during their growth phase, or one that was either 20 per cent higher or lower in crude protein. The HIGH or LOW protein rations were fed over different time periods and various measures of body and reproductive development were taken throughout the experiment. The different diets had only minor effects on the developing birds and resulted in no change in the number of eggs laid. These results suggest that feeding a high protein diet during the growth phase may not be necessary for proper reproductive development. This is a significant conclusion and suggests that other management decisions are likely to have greater impact on breeder flocks.


Timing of feed restriction and photostimulation
In a related trial, chicks were full fed for either one or three weeks. Growth curves thereafter were designed to merge the two groups by 10 weeks of age. As expected, the 3WK group initially gained much more weight, but upon being feed restricted virtually matched the other group in all respects, including apparent reproductive development, by the end of the 16-week trial. Flock uniformity was better for the 1WK group, presumably due to a smoother transition into feed restriction and less competition for feed from aggressive birds. The pullets were photostimulated at 17, 19, 21 or 23 weeks. As expected, stimulating birds later resulted in delayed onset of sexual maturity, but these birds matured more quickly. Flocks stimulated later came into lay most consistently and had larger early eggs. These results suggest that more mature birds can better respond to photostimulation cues.

The importance of body size
Data were also collected on two commercial breeder flocks from hatch to end of lay. Chick size had little correlation to production traits, while measurements at nine weeks were more predictive of the birds’ performance later on. On average, lighter hens were less productive, while hens that were too heavy tended towards more double-yolked eggs and other reproductive problems.

Next steps
The many data produced during this project are being analyzed in the context of the overall breeder physiology program. In light of the relatively small impact of changing protein levels, future work will concentrate on the effects of varying energy intake and age of photostimulation.
Funding for this project was provided by CPRC, Alberta Agricultural Research Institute and Aviagen.

Workplace exposures of poultry barn workers
There are relatively few data available on the exposure of poultry workers to environmental contaminants. The purpose of this study was to log the amount of time poultry workers spend on various activities on farm and to measure their exposure to environmental contaminants such as ammonia, respirable dust and CO2. Exposures were compared between layer and broiler operations throughout production cycles at different times of the year.
During an earlier study, the tasks of poultry barn workers were recorded during their workshifts and personal exposures were monitored with Personal Environmental Sampling Backpacks
to measure contaminant exposure during the work tasks they conducted.

Ammonia, CO2 and dust
These studies suggest that ammonia exposures for poultry workers do not exceed the 25ppm Time Weighted Average Threshold Limit Value (TLV) set by the American Conference of Governmental Industrial Hygienists (the TLV of a chemical substance is the level to which it is believed a worker can be exposed day after day for a working lifetime without adverse health effects). Similarly, measured CO2 levels did not exceed the 5,000ppm TWA-TLV. Because of the high dust levels, the authors do recommend that poultry workers use N95 or comparable respirators while working in their barns to reduce their exposure to and mitigate adverse effects from respirable dust in the layer barn and broiler barn environment.

Funding for this project was provided by CPRC, the Natural Sciences and Engineering Research Council and Agriculture and Agri-Food Canada.

For more details on any CPRC activities, please contact Gord Speksnijder at The Canadian Poultry Research Council, 483 Arkell Road, R.R. #2, Guelph, Ont., N1H 6H8, phone 289-251-2990, fax 519-837-3584, e-mail, or visit us at

The membership of the CPRC consists of the Chicken Farmers of Canada, Canadian Hatching Egg Producers, Canadian Turkey Marketing Agency, Egg Farmers of Canada and the Canadian Poultry and Egg Processors’ Council. CPRC’s mission is to address its members’ needs through dynamic leadership in the creation and implementation of programs for poultry research in Canada, which may also include societal concerns.

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