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There is considerable debate as to the optimal light intensities for growing chickens. This is influencing regulations and industry practices. The present study examines the preference of broiler chickens for light intensity. A choice system was developed to allow determination of the preferences of broiler chickens for light intensity. This system had three light proof pens each with feeders or waterers but different light intensities. There was a connecting transit pen with a light intensity of 1 to 2 lux. This allowed birds access to the pens each with feeders or waterers. There were markedly more chickens observed in the pens each with feeders or waterers and a light intensity of 20 lux than 5 lux. Moreover, more feed was consumed in the 20 lux pens than 5 pens. There were also high numbers of chickens in the transit compartment with its low light intensity (1 to 2 lux) and no feeders or waterers. Broiler chickens exhibited a preference for 20 lux light intensity for feeding compared to 5 lux light intensity. The present study supports the view that there should be a light intensity of at least 20 lux for the areas around the feeders and also suggests that light intensity may be reduced in other areas for resting and other activities.

Simple SummaryThis project monitored the internal micro-environments of live poultry transport trailers during loading and transport. For the 28 trips evaluated, trailers were modified using common USA industry mitigation practices designed to optimize bird comfort under a wide range of environmental conditions. In the cold season, double boarding of the exterior area of the transport modules elevated the internal temperature more than 8 °C above ambient temperatures as low as −16 °C. However, the temperature elevation may not be sufficient when ambient temperature was below 0 °C. In the warm season, surface wetting of birds and evaporative cooling applied during on-farm loading maintained trailer thermal conditions at or below ambient temperature for part of the road transport. However, this study suggests that additional improvement in equipment design or management is warranted when temperatures are extremely cold or hot.AbstractThis observational study was conducted to characterize the thermal micro- climate that broilers experienced in commercial poultry transporters under various weather conditions and typical management practices in the South Central USA. We continuously monitored temperature and relative humidity in 45 interior locations of 28 fully-loaded commercial trailers over 2 year spans from 2015–2016 in South Central USA. In the cold season, double boarding of the exterior area of the transport modules maintained temperatures at least 8 °C warmer than ambient temperatures as low as −16 °C. Overall, temperature at all locations decreased as transporters traveled from farms to processing plants during winter trips with double boards. In the hot season, assistance by evaporative cooling during on-farm loading resulted in interior temperatures within ± 2 °C of ambient conditions (up to 36 °C) during road transport. In the summer months, trailers uniformly gained 2 °C as vehicles travelled for 45 min from farms to plants. Apparent equivalent temperatures of the monitored summer trips averaged 80.5 °C, indicating possible heat stress conditions based on the thermal comfort zones defined by literature index values. For longer trips, cooling assistance on the farms may be insufficient to prevent temperatures from rising further into extremely hot conditions in the transporters, leading to a dangerous thermal environment.

ObjectiveTo determine the effect of bacitracin methylene disalicylate (BMD) and feed changes on gastrointestinal integrity, endotoxin permeability, and morphometric parameters in the duodenum of broilers.ResultsBirds were raised on a starter diet without growth promoting antibiotics for 31 days then switched to a grower diet. Four of the pens including 50 g/ton of BMD while 4 pens remained antibiotic free. Eight birds per treatment were sampled prior to the feed change and at 3 and 7 days following the feed change. Gastrointestinal integrity and endotoxin permeability in the duodenum were determined using a modified Ussing Chamber and an adjacent section fixed in 10% formalin for morphometric analysis. Data were analyzed using Proc Glimmix of SAS with the model fitting BMD treatment, time, and the interaction of BMD treatment and time as fixed effects. Intestinal integrity increased at d 3 and 7 compared to prior to the feed change and addition of BMD (P > 0.001) and villus height was decreased with BMD supplementation (P = 0.049). All other tested effects similar (P > 0.1). In conclusion, the practice of changing feed had a greater effect on intestinal health than addition of BMD. However, the factors driving these differences 42 are unclear.Electronic supplementary materialThe online version of this article (doi:10.1186/s13104-017-2781-8) contains supplementary material, which is available to authorized users.

Abstract. Strategies for quantifying heat loss of broilers on live-haul trailers would be beneficial, particularly under conditions of environmental extremes. We have developed an electronic chicken (a self-contained, temperature-controlled heat source) to simulate the sensible heat loss of a live broiler during the transit and holding periods in commercial live-haul trips. The simulated electronic chicken is an aluminum box, having surface area equivalent to a 2.3 to 2.8 kg broiler chicken (0.13 m2), with a thermostatically controlled power source to maintain the internal temperature at 41°C (typical broiler core body temperature). Different cover materials were tested to identify an appropriate cover that resulted in measured values of electronic chicken heat production being similar to published values of sensible heat production for broilers. A double layer of fleece fabric provided a reasonable match. The sensible heat loss of the electronic chickens exhibited positive correlation with exposed wind, and a positive correlation with temperature gradient between internal and external environment. Wetting the fabric cover of electronic chickens only slightly increased heat loss as compared to the dry fabric cover. Wet fabric cover experienced lower heat loss than that expected from the wetted surface of a live chicken, therefore heat loss under the wet scenario would be underestimated. Electronic chickens were installed in modules on trailers with live chickens during commercial live-haul process under various environmental conditions and different management practices. Measured heat losses from electronic chickens were in the range of 8.2 to 20.3 W with outside temperature of -17°C to 3.0°C in winter, and 4.5 to 6.7 W with 28°C to 34°C in summer. Based on literature-reported sensible heat loss under thermoneutrality, it was determined that the measured air temperature inside the live-haul modules on the trailer in the range of 11°C to 25.1°C during transit (outdoor temperature range of 1.7°C to 22.2°C) and 5.3°C to 21.7°C during holding (outdoor temperature range of -9.1°C to 19.8°C) would allow the live chickens to regulate heat by their metabolism and stay comfortable. For the holding period, the winter trips were mostly in the zone of thermal comfort. In summers, hyperthermic conditions were possible during transit, although additional cooling due to surface wetting of birds as a result of misting (on the farm prior to beginning the transit) could have been beneficial but not detectable by electronic chickens. The electronic chickens can be used effectively as a model to evaluate and identify conditions that cause thermal stress conditions during live-haul conditions and to design systems and strategies to alleviate that stress. Keywords: Broiler transport, Physiological stress, Thermal micro-environment, Thermoneutral zone.

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