Poultry and livestock units: screening for environmental impact
Almost every commercial poultry shed is Schedule 2 development, so the screening opinion decides the scheme. How ammonia, permitting and odour evidence fit together.
Poultry unit EIA screening is decided by two numbers and one judgement. The numbers are the Schedule 1 capacity thresholds in the Town and Country Planning (Environmental Impact Assessment) Regulations 2017, which make an environmental statement mandatory, and the 500 square metre floorspace figure in Schedule 2, which makes screening mandatory. The judgement is whether a Schedule 2 development is likely to have effects of the kind the Regulations are concerned with.
Most new broiler and layer buildings clear the Schedule 2 floor area comfortably and sit below the Schedule 1 capacity, so the screening opinion is where the scheme is won or lost. Ammonia is usually the deciding issue.
Where the EIA Regulations bite
Schedule 1 to the 2017 Regulations lists installations for the intensive rearing of poultry or pigs above stated capacities: more than 85,000 places for broilers, more than 60,000 places for hens, more than 3,000 places for production pigs over 30 kilogrammes, and more than 900 places for sows. A development at or above those figures requires an environmental statement without any screening exercise.
Below them, intensive livestock installations fall within Schedule 2 where the area of new floorspace exceeds 500 square metres. A single modern broiler house exceeds that on its own, so almost every commercial poultry proposal is Schedule 2 development.
Being Schedule 2 does not mean an environmental statement is required. It means the local planning authority has to take a screening decision, applying the selection criteria in Schedule 3 on the characteristics of the development, its location and the type and characteristics of the potential impact.
Where an environmental statement is required, regulation 18 requires it to be prepared by competent experts and the applicant to provide a statement of the expertise used. That is a legal requirement, not a matter of good practice, and an AI-assisted draft is a starting point for those experts rather than a substitute for them.
Schedule 2 and the 500 square metre trigger
Two counting questions come up constantly.
Cumulative development counts. Adding a fourth shed to a site with three existing ones is assessed against the whole installation, not the new building in isolation, and authorities that ignore this find the decision challenged. Where the site has been extended in stages, set out the full history in the screening request.
Ancillary structures count towards floorspace where they form part of the installation. Feed bins, a biomass boiler house, an ancillary store and the muck store are all part of the development being screened even though only the sheds hold birds.
A screening request goes in under regulation 6 with a plan, a description of the development and a description of the likely effects. The authority normally has three weeks to adopt a screening opinion, extendable by agreement. Where you expect the answer to be negative, provide the ammonia modelling with the request rather than waiting to be asked. A screening opinion that says no environmental statement is required, supported by the modelling, is the most valuable piece of paper in the file.
The environmental permit runs on its own track
Planning permission and environmental permitting are separate consents with separate decision-makers, and neither determines the other.
Intensive farming installations need a permit from the Environment Agency under the Environmental Permitting (England and Wales) Regulations 2016 where they exceed the relevant capacities, which sit below the EIA Schedule 1 figures. In broad terms, poultry rearing above 40,000 places, production pigs over 30 kilogrammes above 2,000 places and sows above 750 places are permitted installations. Check the current thresholds, because the schedule is amended.
The permit deals with emissions, best available techniques, manure management and monitoring. Planning deals with land use, landscape, amenity, highways and the acceptability of the building in that location. Councils sometimes try to condition matters the permit controls, and national policy discourages duplication, so the practical approach is to state clearly in the Planning Statement which regime handles what.
Do not assume a permit removes the planning objection. A unit can hold a permit and still be refused on landscape grounds.
Ammonia and nitrogen deposition on designated habitats
This is where intensive livestock applications actually fail.
Ammonia emitted from housing, from the muck store and from land spreading disperses and deposits as nitrogen on nearby habitats. Sensitive habitats have published critical levels for ammonia concentration and critical loads for nitrogen deposition, and the critical level is lower where lichens and bryophytes are a feature of the site.
The assessment runs in stages. A screening model estimates the process contribution at each designated site within the relevant distance. Where the contribution is a small fraction of the critical level or load, the effect is screened out. Where it is not, detailed dispersion modelling follows, and where a European site is involved the authority must consider the requirements of the Conservation of Habitats and Species Regulations 2017, including appropriate assessment.
Natural England is the statutory consultee for sites of special scientific interest and European sites. Their advice frequently drives the outcome, and it is worth obtaining an early view rather than discovering it at week 11 of the determination period.
Mitigation exists: abatement on the ventilation, tree belts to intercept deposition, revised siting, reduced stocking, and manure management changes. None of it comes free, and all of it needs to be designed in rather than offered at the end.
Odour, dust and bioaerosols near dwellings
Where housing lies within a few hundred metres, expect odour and dust to be raised by neighbours and by environmental health.
The odour assessment follows the source, pathway and receptor structure used in the Institute of Air Quality Management guidance, and for larger units dispersion modelling is normal rather than exceptional. An Odour Assessment should cover the housing, the muck store, the loading of muck for removal and the depopulation events, because the peak conditions are what generate complaints.
Dust and bioaerosols arise mainly during catching and clean-out. Set out the frequency, duration and the mitigation for each. Vehicle movements at those times are a separate amenity issue.
Traffic, lighting and the working pattern
The traffic profile of an intensive unit is uneven and that unevenness is the point.
Routine feed deliveries are predictable. Catching and depopulation is not: teams arrive at night, artificial lighting is used, and a run of large vehicles uses the lane over a few hours. Describe that pattern honestly with vehicle types and timings, because a highway objection based on a guess is harder to answer than one based on your own figures.
Lighting design should follow the Institution of Lighting Professionals guidance on obtrusive light, with the environmental zone identified. In open countryside the zone is usually the most sensitive, and unshielded floodlighting will attract a condition or a refusal.
On the buildings themselves, a Landscape and Visual Impact Assessment carries real weight in open countryside. Long low sheds are hard to hide. But colour and ground modelling can take a surprising amount of bulk out of a view. Roof pitch and the position relative to existing farm buildings do more than planting, which takes 15 years to work.
Where new buildings take land out of production, an Agricultural Land Classification survey shows whether best and most versatile soils are affected. On a small footprint the point is usually neutral, but it is asked for.
Sequencing screening, permit and application
Run the three processes in this order and the programme holds together.
- Commission the ammonia screening model first, before the shed positions are fixed. Siting is the least costly mitigation available.
- Request a screening opinion with the modelling attached, and ask for a scoping opinion at the same time if an environmental statement looks likely.
- Start the permit application in parallel, since the Environment Agency's timescales are independent of the council's.
- Submit the planning application once the screening opinion is adopted, with the odour, landscape and highways evidence complete.
Applicants who submit planning first and model later spend the determination period reacting to Natural England. Applicants who model first usually get a negative screening opinion and a much quieter application.
Enter your postcode on PlanScope to see which reports an intensive livestock proposal is likely to need.
This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. An environmental statement must be prepared by competent experts under the EIA Regulations 2017. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
When does a poultry unit need an environmental statement?
Automatically where capacity exceeds the Schedule 1 figures in the EIA Regulations 2017: more than 85,000 broiler places, 60,000 hen places, 3,000 production pig places over 30 kilogrammes or 900 sow places. Below those, the development is Schedule 2 where new floorspace exceeds 500 square metres and the council must take a screening decision.
Does existing development count towards the screening threshold?
Yes. A new shed on a site with existing housing is assessed as part of the whole installation rather than in isolation, and ancillary structures such as feed bins, boiler houses and muck stores count towards floorspace. Set out the full development history in the screening request so the authority can see the cumulative position.
Is an environmental permit the same as planning permission?
No. The Environment Agency issues permits for intensive farming installations under the Environmental Permitting Regulations 2016, covering emissions, best available techniques and manure management. Planning deals with land use, landscape, amenity and highways. Holding a permit does not prevent a refusal on landscape or amenity grounds.
Why does ammonia decide so many applications?
Because ammonia from housing, muck stores and spreading deposits as nitrogen on nearby habitats, and sensitive sites have published critical levels and critical loads. Where modelling shows the process contribution is more than a small fraction of those figures, detailed dispersion modelling and, for European sites, appropriate assessment under the Habitats Regulations follow.
When should the ammonia modelling be done?
Before the shed positions are fixed. Siting and ventilation arrangement are the least costly mitigation available, and both are effectively locked once a layout is drawn. Submitting the modelling with the screening request often produces a negative screening opinion and removes the main reason for objection from Natural England.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.