Identifying effective early life management systems to optimise the health, welfare and performance of commercial broiler chickens

Abstract

Demand for chicken meat has increased considerably, howeverpublic concern for farm animal welfare has intensified. The aim of this thesiswas to identify and assess strategies for addressing early stressors in broilerchickens that can affect health, welfare, and performance.

Firstly, several early life systems were compared, includingtraditional hatching (control), wet feed at placement, access to water or feedand water in the hatchery, and in-house hatching. Performance in alternativesystems was similar to or poorer than in the control. In-house hatched chickshad heavier bursas, tended towards poorer chick quality, and had reducedpododermatitis. Access to feed and water in the hatchery also reducedpododermatitis, however birds had greater susceptibility to tibial dyschondroplasia.

A second study investigated the practice of long photoperiodsduring the first week of life. Treatments included an industry standardlighting programme, increased darkness, and optional-access dark shelters.Neither shorter photoperiods nor dark shelters negatively affected early oroverall performance. Dark shelters were heavily used and improved leg health,reducing hock burn and improving 28 day gait score.

A further study used audio data and deep learning models toclassify distress vocalisations. Distress was highest immediately afterplacement and declined as chicks acclimatised. Daytime dark periods had littleeffect, whereas nighttime darkness increased distress vocalisations.

The final study analysed an industry dataset to identifyexternal and on-farm factors influencing broiler outcomes (7 day and totalmortality, 7 day and 35 day corrected liveweight, pododermatitis, hock burn,carcass downgrades). Season, parent flock age, and hatchery were consistentlyinfluential, with stocking density and flock size also important. Relativehumidity was the most impactful on-farm factor. Only 7.5% of flocks met “ideal”criteria (where target performance was achieved for all outcomes) with stockingdensity, chick paper type, and parent flock age the most influential