The Impact of Range Use on Flock Uniformity in Commercial Free Range Laying Hens

Published: December 4, 2024

By: T.Z. SIBANDA 1, D. SCHNEIDER 2, M. WELCH 2, Z. IQBAL 1, A. COHEN-BARNHOUSE 1, M. KOLAKSHYAPATI 1, N.K. MORGAN 1 and I. RUHNKE 1 / 1 School of Environmental and Rural Science, University of New England, Armidale; 2 School of Science and Technology, Precision Agriculture Research Group, University of New England, NSW.

Flock uniformity is crucial to increase the performance and profitability of commercial egg production (Corzo et.al, 2004). Obtaining flock uniformity in a free-range system may be challenging due to the variation in feeding and ranging behaviour of individual birds.

The current study investigated the effect of body weight on initial range utilization and flock uniformity in two free-range laying flocks. A total of 6,250 Lohmann Brown hens were weighed and assigned to 2 identical commercial free-range sheds (Flock A; Flock B) at 16 weeks of age. Each of the sheds was sub-divided into 5 pens holding 625 hens/pen, allowing for 5 replicates/flock. Hens had access to the range daily from 9am to 8pm at 17 to 21 weeks of age with individual time on the range monitored using radio frequency identification (RFID) leg bands. Individual body weight was obtained at 16 and 21 weeks of age, and assigned to the individual RFID number of the hens. Hens in Flock A had the initial standard average body weight of 1.36kg while Flock B was below the standard weight (1.27kg) at 16 weeks of age. Flock uniformity was calculated as the percentage of hens within plus or minus 10% of the average body weight. Average time on the range, number of events at range, body weight, flock uniformity, change in flock uniformity data were analysed by one-way ANOVA, using SPSS Statistics v.24.

The results (Table 1) indicate that hens of Flock B with lower initial body weight spent significantly less time on the range and gained more weight (P < 0.001) to 21 weeks of age compared to hens of Flock A. Flock uniformity of Flock B increased by 7% while the uniformity of hens in Flock A (hens that spent significantly more time ranging) decreased by 2.8% (P = 0.003).

Table 1 - The effect of range use on flock uniformity and body weight†

In conclusion, hens with lower body weight at placement spent significantly less time on the range, gained more weight and had increased change in flock uniformity compared to hens with high body weight at placement.

ACKNOWLEDGEMENTS: Australian Eggs and Poultry CRC for financial support and Bradley Dawson for technical assistance.

Presented at the 29th Annual Australian Poultry Science Symposium. For information on the next edition, click here.