29 research outputs found
Energy allocation and behaviour in the growing broiler chicken
Broiler chickens are increasingly at the forefront of global meat production but the consequences of fast growth and selection for an increase in body mass on bird health are an ongoing concern for industry and consumers. To better understand the implications of selection we evaluated energetics and behaviour over the 6-week hatch-to-slaughter developmental period in a commercial broiler. The effect of posture on resting metabolic rate becomes increasingly significant as broilers grow, as standing became more energetically expensive than sitting. The proportion of overall metabolic rate accounted for by locomotor behaviour decreased over development, corresponding to declining activity levels, mean and peak walking speeds. These data are consistent with the inference that broilers allocate energy to activity within a constrained metabolic budget and that there is a reducing metabolic scope for exercise throughout their development. Comparison with similarly sized galliforms reveals that locomotion is relatively energetically expensive in broilers
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OBSERVATIONS OF A MIXED-SPECIES FLOCK OF BIRDS FORAGING ON EUPHAUSIIDS NEAR ST MATTHEW ISLAND, BERING SEA
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OBSERVATIONS OF A MIXED-SPECIES FLOCK OF BIRDS FORAGING ON EUPHAUSIIDS NEAR ST MATTHEW ISLAND, BERING SEA
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Foraging radii and energetics of least auklets (Aethia pusilla) breeding on three Bering Sea Islands
The authors studied the relationship between the foraging radius and energy economy of A. pusilla breeding in colonies on three islands in the Bering Sea (St Lawrence, St Matthew, and St George Islands). The distance to which auklets commuted on foraging trips varied by more than an order of magnitude c5-56 km), but mean field metabolic rate did not vary significantly among birds from the three islands. The authors modeled the partitioning of energy to various activities and hypothesized that the added cost of commuting incurred by auklets from St Lawrence Island (foraging radius, 56 km) was offset by reduced energy costs while foraging at sea. Data indicated that auklets from St Lawrence Island fed on larger, more energy-rich copepods than auklets from St Matthew Island (foraging radius, 5 km). -from Author