Agricultural and Biosystems Engineering Publications

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Agricultural and Biosystems Engineering

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Transactions of the ASAE





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The posthatch energetics of neonatal chicks exposed to a variety of environmental conditions was investigated. Specifically, moisture production (MP), sensible heat production (SHP), total heat production (THP), respiratory quotient (RQ), and body mass loss (BML) of breeder chicks during a 50 h posthatch holding period in shipping containers at the ambient temperatures of 20, 25, 30, and 35°C with the concomitant relative humidity of 40%, 30%, 22%, and 17%, respectively, were determined. The average responses of the chicks under these environmental conditions were respectively, 3.8, 4.0, 4.1, and 4.6 g·(kg·h)–1 MP; 7.8, 6.4, 5.7, and 5.2 W·kg–1 SHP; and 10.3, 9.1, 8.5, and 8.4 W·kg–1 THP. RQ was independent of the temperature (P = 0.59) and averaged 0.75. BML increased with temperature (P < 0.01) and averaged 5.3, 5.7, 5.9, and 6.3 g·chick–1, or 13.5%, 14.4%, 14.9%, and 15.9% of the initial body mass, respectively. Chick mortalities at 20°C and 25°C (1.09% and 0.71%) were higher than those at 30°C and 35°C (0.28% and 0.33%) (P < 0.01). Based on the criteria of least thermoregulatory efforts and mortality, the thermal neutrality for the unfed, group-housed neonatal chicks was between 30°C and 32°C. Moreover, the metabolic rate of the fasting chicks at thermal neutrality, 77 kcal·day–1/kg0.75 of this study agreed well with the literature value of 70 kcal·day–1/kg0.75 for fasting homeotherms. This study provides unique data for the design and operation of ventilation and environmental control systems during transportation of baby chicks.


This is Joumal Paper No. J-16736 of the Iowa Agriculture and Home Economics Experiment Station, Iowa State University, Project No. 3355. Funding for this study was provided in part by Hy-Line International. Mention of company or product names is for presentation clarity and does not imply endorsement by the authors or Iowa State University; nor exclusion of any other products that also may be suitable for the application.

This article is from Transactions of the ASAE 39, no. 6 (1996): 2249–2254.



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American Society of Agricultural Engineers



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