Reducing ammonia emissions from broiler chicken production

Background

Broiler production has been a growth area in Welsh agriculture in recent years. The growing demand for chicken has provided viable diversification opportunities for a number of Welsh farmers. An inevitable consequence of any form of poultry farming is the production of ammonia, through the natural breakdown of urates within poultry manure. Ammonia emissions from poultry production can have a number of significant impacts on the environment, bird welfare, and broiler economics.

High levels of ammonia emissions are cited as one of the main reasons for permits being refused or for planned expansion being prohibited. Modern housing with better ventilation and heating along with improved litter has reduced ammonia emissions. 

Further improvements may be possible by using ammonia-reducing additives either applied directly to the litter or supplied to the birds via the drinking water.

Two established commercial broiler producers, with modern buildings and many years’ experiences of producing poultry for the UK market, were involved in this one year project which investigated whether these additives can reduce their ammonia emissions.

Three different commercially available ammonia reducing additives were tested on each farm. On both farms, one house was used for the trial and the other as a control. Each product was tested for one complete broiler flock cycle (2 months) and the following variables were recorded:

1.    Ammonia levels within the houses
2.    In house temperature
3.    Foot pad condition, hock and gait scoring
4.    Feather condition
5.    Litter condition
6.    Mean bird liveweight
7.    Flock mortality
8.    Feed intake

Project Outcomes:

• Ammonia emissions were actually slightly lower in the control houses than in those with products added. Again, the differences were very small, at only around 3%. Due to the small sample size, it impossible to know for sure whether the differences observed were due to chance or represented true effects from the additives.
• The average liveweight in the houses with product was slightly lower than in the control houses, even though the average age at processing was very slightly higher. The differences are again marginal though.
• The use of additives has a potential to result in a higher litter dry matter in poultry houses compared to those receiving no additives. If this difference is real, then the use of products would be consistent with the aim of keeping litter as dry as possible.
• The project highlighted some potential difficulties in calculating ammonia emission factors in commercial settings and further studies may be needed to resolve methodology issues for future projects.