Caged laying hens are prone to calcium deficiencies, resulting in osteoporosis and egg quality deterioration during the later phase of the laying cycle. Fluorescent light and light-emitting diodes (LEDs), which are widely used in poultry houses now, are both deficient in ultraviolet (UV) light, the lack of which is detrimental to chickens’ welfare and health. This study was conducted to investigate the effects of UVB light supplementation using LEDs on the bone traits, blood parameters, laying performance, and egg quality for caged laying hens at 68–75 weeks. In total, 120 Jingfen laying hens were randomly assigned to four different groups, with three replicates in each group (10 hens in each cage as a replicate). UVB-LED lamps installed under the feed troughs were used to provide UVB light (296–316 nm) for the birds in the three treatment groups (1 h, 2 h, and 3 h UVB supplementation per day, respectively), while the control group was not exposed to UVB-LED light. Bone traits, egg quality, and amounts of calcium (Ca), phosphorus (P), 25-hydroxyvitamin D₃ (25(OH)D₃), 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃), and 7-dehydrocholesterol (7-DHC) in both the serum and egg yolks were tested during the experiment. The results demonstrated that UVB-LED exposure significantly increased the bone mineral density (BMD), egg production, and yolk 1,25(OH)₂D₃ concentrations (p < 0.05), and reduced the content of serum 7-DHC (p < 0.05), especially in the 2 h/day group; however, it did not improve egg quality, vitamin D metabolites, or photoproducts in the serum and yolk 25(OH)₂D₃ concentrations (p > 0.05). This study concluded that UVB supplementation using LEDs had a positive effect on caged laying hens during the later phase of the laying cycle.

The temperature inside broiler houses is crucial to broiler health, welfare, and productivity. High stocking density in broiler houses can easily lead to nonuniform temperature conditions, which would cause broilers to suffer cold and heat stress. It is essential to assess the temperature distribution inside broiler houses and investigate the factors that affect temperature uniformity. Therefore, in this study, temperature, wind velocity, and differential pressure were monitored in the aisle, at the sidewall inlet, and outside the sidewalls of a commercial stacked-deck cage broiler house in Northeast China aiming to continuously monitor the temperature throughout the entire fattening period. Results show that the maximum temperature difference increased from 1.85 °C to 6.43 °C, while the daily fluctuation increased from 2.27 °C to 5.80 °C. The highest temperature was consistently recorded at the side of the exhaust fans (p < 0.001) in the longitudinal direction. In the lateral direction, the temperature difference varies periodically with solar radiation. The average temperature at the southern location (23.58 ± 1.97 °C), which faces the sun, was higher than that at the northern location (23.35 ± 1.38 °C), which is in the shade, during periods of solar radiation (p < 0.001) at the last testing period. However, without solar radiation, the northern location recorded a warmer temperature (23.19 ± 1.41 °C) compared to the southern location (22.30 ± 1.67 °C) (p < 0.001). The lateral temperature differences are strongly positively correlated with solar radiation and wind speed (p < 0.001). In conclusion, the inside temperature nonuniformity and fluctuation increased as the broiler age increased, which affected the production performance of broilers. Nonuniform solar radiation and wind speed can lead to differences in the inlet temperature and air volume between both sidewalls, thereby affecting the uniformity of the lateral temperature inside the house.