Pollution - Odour

• There are many different potential sources of pollution associated with industrial poultry units, but the major one is obviously droppings and their unpleasant odour, although decomposing carcasses can also make a contribution if not correctly managed.

• The Red Tractor scheme allows (1) for a mortality rate of up to 5%, which would represent approximately 60 fallen animals per week. These have to be identified, collected, stored and then disposed of in a manner that will not generate odour.

• Anyone living in the country will be familiar with the particularly unpleasant odour of chicken manure, which is being used increasingly as a fertilizer, due to the number of industrial poultry units springing up around the country.

• This odour is often associated with ammonia, but there are many different chemicals contributing to this smell, some of them toxic, and some contributing to Greenhouse Gas Effects and global warming.

1,000 laying hens will excrete approximately 120Kg droppings per day (2), which for 64,000 hens is equivalent to:

54 tonnes per week

2,800 tonnes per annum

• Odour from the droppings can be managed most effectively when they occur in the sheds, but in a Free Range situation, a proportion of the hens will choose to spend time outdoors, where the odour from the droppings cannot be managed.

• If only 25% of the flock spent 8 hours each day out of doors, then this would represent approximately 4.7 tonnes per week of wet manure lying on the surface of the soil, maximising the release of ammonia and malodours.

• For hens kept in sheds, it is possible to control ammonia emissions by reducing the moisture content of the droppings, but drier droppings are more likely to lead to dust formation, which is extremely hazardous (3).