Ammonia and Carbon Dioxide Emissions vs. Feeding and Defecation Activities of Laying Hens

Abstract

This study characterizes dynamic ammonia (NH3) and carbon dioxide (CO2) emissions associated with feeding and defecation activities of laying hens. Manure handling scheme used was reflective of commercial manure-belt house operation. Four dynamic emission chambers and measurement system was developed, featuring continuous measurement of the following variables for each chamber: (a) NH3 concentrations of inlet and outlet air, (b) air temperature and relative humidity, (c) airflow rate, (d) feeder weight and thus feeding activity, and (e) manure pan weight and thus defecation activity. Daily feed consumption of the hens averaged 103 g/hen-d and fresh manure production averaged 125 g/hen-d. Ammonia emission rate ranged from 1.26 mg/hen-hr on the first day of manure accumulation to 9.26 mg/hen-hr after 7 d of manure accumulation. CO2 emission rate averaged 3.41 and 2.47 g/hen-hr during light and dark hours of the day, respectively. Dynamic NH3 emissions tend to be inversely related to defecation events as manure accumulates. Results from this study will contribute to the development and/or validation of process-based farm emission model for predicting NH3 emissions from laying-hen houses. The dynamic nature of NH3 emissions vs. defecation may also provide insight concerning application timing of manure treatment agents to mitigate NH3 emissions from laying-hen houses.