A South African study published in June this year has made a breakthrough discovery that could transform how broiler farmers manage their flocks and maximise profits.
By Maile Matsimela, digital editor of African Farming
A groundbreaking study conducted by researcher Lubabalo Bila from the Department of Animal Production at Potchefstroom College of Agriculture has revealed that farmers can accurately predict the body weight of their Ross 308 broiler chickens using nothing more than a measuring tape and some simple calculations.
Ross 308 chickens are primarily bred for meat production and their body measurements can tell farmers a lot about their growth potential, market value and health status.
This exceptional growth makes Ross 308 chickens particularly profitable compared with other livestock, but it also presents farmers with the challenge of accurately monitoring growth rates to optimise feeding strategies and determine the perfect time for slaughter.
Bila’s research involved studying 120 Ross 308 chickens, of which 60 were males and 60 females, at five weeks of age, just one week before their typical market readiness. The study used two computer programs designed to find patterns in the data and predict weights based on body measurements.
The researcher measured six key body parts using a standard measuring tape: wing length, beak length, shank length, body girth, body length and shank circumference. These measurements were then compared with actual body weights measured using a sensitive scale.
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Body Measurements An Accurate Predictor Of Live Weight
What emerged from this analysis was remarkable: Specific body measurements could predict live weight with impressive accuracy.
For male Ross 308 chickens, the research revealed that body length emerged as the best predictor of body weight. Bila discovered that body length was “the body measurement most strongly connected to body weight” in male birds.
Other measurements also showed positive connections: shank length, wing length and body girth all helped predict weight. However, interestingly, beak length showed a slight negative connection with body weight, suggesting that longer beaks don’t necessarily mean heavier birds.
For practical use, this means farmers can measure the body length of their male chickens and get a reliable indication of their weight without needing expensive scales for every bird in the flock.
The research revealed fascinating differences between male and female Ross 308 chickens. In females, shank length emerged as “the key factor influencing body weight”, rather than body length, as seen in males.
Female body weight showed positive connections with shank circumference and body girth, and also displayed a negative connection with beak length. Most intriguingly, the study found that “beak length showed a strong positive connection with shank length” in females, suggesting these measurements are closely linked.
This gender-specific finding has profound implications for farmers, as it means different measurement strategies should be employed for cockerels and pullets to achieve the most accurate weight predictions.
Although both computer programs showed promise, one method emerged as the clear winner and proved more reliable for practical farm use. This superior performance means farmers can expect greater accuracy when estimating their birds’ weights, leading to more precise management decisions.
Bila emphasises that this approach enables farmers to “optimise feed usage by tailoring feed allocation based on growth potential, thereby improving feed conversion efficiency”.
Rather than using expensive scales to weigh every bird, farmers can now measure key body dimensions and make informed decisions about feed allocation, ensuring that birds with the highest growth potential receive optimal nutrition while avoiding wasteful overfeeding of slower-growing individuals.
The research also enables farmers to “make informed decisions regarding the timing of marketing or slaughter, maximising profitability” by identifying which birds are closest to their target weights without the stress and labour involved in catching and weighing individual animals.
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Cost-effective Management Practices
One of the most compelling aspects of this research lies in its cost-effectiveness. According to Bila’s findings, “this approach is particularly useful in settings where scales or live weight measurements are not available, facilitating cost-effective management practices”.
This method allows farmers to achieve “accurate prediction of body weight based on body measurements”, which helps them “identify chickens with the highest growth potential for optimal feeding and management strategies” while simultaneously helping to “reduce feed costs by targeting resources toward more profitable birds”.
This targeted approach prevents both overfeeding and underfeeding, optimising overall production efficiency and translating directly into “better income generation” for farming operations.
The beauty of this research lies in its simplicity. Farmers need only a measuring tape and basic record-keeping to implement these findings. For male chickens, focus on measuring body length. For females, prioritise shank length measurements.
By taking these measurements at five weeks of age, farmers can predict final weights and adjust their management strategies accordingly. This could involve sorting birds into different feeding groups, identifying early marketers or selecting the best performers for breeding purposes.
Bila acknowledges that “further studies with larger sample sizes are needed” to enhance the usefulness of findings. The researcher also suggests that “differences in environmental, dietary, and genetic factors may affect results”.
Looking forward, the research points to exciting possibilities, including testing the method on other chicken breeds and exploring how feed, climate and housing conditions might affect body weight predictions.
