POULTRY CONFLICT
Existing meat chicken farms were traditionally located in urban fringe areas due to the proximity of processing plants and markets (McGahan et al. 2002). Over the last decade the combined effects of urban and rural residential expansion, increased environmental awareness, significant growth in meat chicken consumption, the need for individual farms to expand to remain competitive, and the absence of effective planning strategies or controls have increased the risk of conflict.
Increasing land prices limit the capacity of existing poultry farms to acquire additional buffer areas and the substantial investment in existing infrastructure inhibits relocation. Careful identification and management of environmental and amenity concerns, particularly odour, is vital for the sustainability of individual farms and the current industry.
Additional information on best practices is provided in the NSW Meat Chicken Guidelines currently being finalised. The development of an Environmental Management Plan for the farm can also help identify and document relevant actions.
MEAT CHICKEN PRODUCTION AND ODOUR GENERATION WITHIN SHEDS.
Chickens for meat production (broilers) are placed within sheds on meat chicken farms as day-old chicks on a bed of dry organic litter (e.g. sawdust, planner shavings, rice hulls). During the subsequent weeks the birds grow rapidly and the amount of manure they excrete increases. The bedding litter (including manure, dust and feathers) begins to break down, creating odorous compounds which then volatilise. The atmospheric emissions that result can create a source of conflict if houses or community facilities are located within the affected area.
Bird density (kg per square metre), shed temperatures and odours peak at around 5 to 6 weeks, at which stage a proportion of the birds are removed (‘thinned’). The odour intensity is maintained while the remainder continue to grow until final harvest at around 6 to 8 weeks. A short break typically follows during which the used litter is removed, the sheds are thoroughly cleaned and fresh litter is put in place before a new batch starts. Most complaints relate to the end of the cycle or to the clean-out of litter but odour has been reported as a significant nuisance as early as 3 weeks into the cycle.
The factors contributing to odour generation from poultry sheds are complex. While the dominant odorous compounds are ammonia, hydrogen sulfide and mercaptans, some 75 compounds have been recognised within meat chicken sheds (Jiang & Sands 2000, McPherson 2000). Some compounds (e.g. sulfides) are more readily detected by humans than others or are perceived as more offensive even in low concentrations. The combination of compounds may also mask certain odours or create an odour that is greater than the sum of the individual components (McPherson 2000). Additionally, perceptions of an odour’s acceptability and individual capacity to detect particular odours can vary greatly.
The type of compounds produced within meat chicken sheds and their concentration is influenced by the nature and rate of biodegradation within the litter (McGahan et al. 2002). High litter moisture content, low oxygen levels, small particle size, high temperatures and low pH encourage anaerobic bacterial activity and the generation of odours. The rate at which the compounds subsequently volatise is influenced by litter pH and temperature, ventilation rates and climate.
Control of the factors summarised in Table 1 is therefore important for reducing odour levels and the potential for conflict.
Table 1. Factors affecting odour generation in meat chicken sheds
ODOUR CONTROL PRINCIPLES.
Resolving conflict is difficult and costly. Preventative actions include minimising the number of people that may be affected by appropriate site selection and shed orientation (including fan direction), purchasing additional buffer lands, or using effective land use planning controls to prevent encroachment.
Where such options are no longer relevant, the most effective strategy is to manage odour-generating processes at the source and maintain positive communication with neighbours.
Odour impacts can also be reduced by dispersing (diluting) odours before they reach potential receivers. How well this works depends on the relative separation distance and the number and direction of sensitive receivers. The frequency, intensity, duration and offensiveness of the odours are also critical.
Odour controls at the receiver are rarely viable and only warrant consideration where all other approaches remain ineffective. For example, installing air conditioning in odour-affected houses does not control odour outside the treated building and is expensive if there are multiple houses to treat.
COMMUNICATION.
Even on well-managed poultry farms, odour will be generated. Keeping in touch with neighbours can reduce the risk of con?ict by helping them understand the poultry production process, the steps being taken to reduce potential problems and practical limitations.
Open communication channels also allow feedback and provide an opportunity to reduce odour, noise or dust problems before significant conflict occurs. Relatively minor adjustments to the timing of shed clean-outs, litter-spreading, management standards or vehicle movements may be all that’s necessary. It may be possible to also avoid the coincidence of peak odour risk periods or activities with special social events planned for a neighbouring property by mutually adjusting either the timing of poultry operations or the event.
Meat chicken farms in proximity to existing residences are encouraged to maintain a daily log of weather conditions (prevailing wind direction and strength, temperature) and farm activities to assess the cause of any reported conflict incident more accurately. This is particularly important where there might be many odour sources or an existing history of conflict. If future expansions are proposed, complaints and activity logs can also demonstrate the effectiveness of current management practices in avoiding conflict.
Author.
Glenda Briggs.
