Summary

Leg weakness remains a considerable concern for broiler chicken welfare under commercial production conditions, whether in confined or under free range systems. Project 6193 (Egg incubation and broiler chicken leg weakness) has determined an effect of egg shell temperature (EST) during incubation on subsequent bone mineralisation and broiler leg strength at 5-6 weeks of age as measured by Latency To Lie (LTL) tests. This was established in a Cobb breeder line but effects have also been shown in the Cobb and Ross broiler lines. Optimal EST for leg strength has been found to be different to EST described as optimal for hatchability, chick quality and broiler performance and will differ between the broiler breeds. Determination of the optimal EST for both broiler lines that will not adversely affect other performance parameters will lead to improved bird welfare without compromising performance. Further it is proposed to evaluate post-hatch treatments, such as environmental enrichments (such as perches, hay bales), nutritional strategies, lighting and management practices following changed incubation profiles that may further enhance broiler locomotory ability during growth. This will be achieved by studying varying incubation profiles based on continuous EST profiles slightly below the currently accepted optimal EST for hatchability, assessing hatch bone mineralisation and LTL at 6 weeks of age ameliorated by the provision of enrichments, differing photoperiod regimes and varying calcium/phosphorus/vitamin D supplementations. An assessment of the current field situation and its relationship with leg strength is also proposed.

Program

Chicken Meat

Research Organisation

The University of Sydney

Objective Summary

1. To establish the effects of different egg shell temperatures (EST)and hatching times targeted during incubation of Cobb 500 and Ross 308 fertile eggs on hatch bone mineralisation and subsequent locomotory ability of late stage broiler chickens.
2. To determine the optimal EST targets for Cobb and Ross broiler eggs to achieve best locomotory ability without deleteriously affecting hatchability, chick quality and broiler performance.