The continual wet summer has prompted vets to urge producers to monitor their birds carefully in the coming weeks and review management systems to reduce the build-up of disease and pests in damp, warm conditions.

“There will be a cumulative effect in terms of disease risk after months of wet weather compared with the wet weather we traditionally have in winter.

“The two seasons are different in terms of disease risks,” warned Michael Clark of The Minster Veterinary Practice, Hereford.

“Poultry producers with birds on range should keep an eye on the health of their flocks in the coming weeks. It’s possible there could be a significant disease backlash because of the conditions birds have been subjected to during the summer.”

Blackhead, gut worm, gape worm, erysipelas and brachyspira have all been identified in flocks recently and are attributing them directly to the wet conditions. Although there have been varying levels of mortality caused by blackhead in some flocks, the insidious impact of worm infestations will have hit production in many others.

Vets are advising producers to undertake faecal egg counts to check for worm burdens in their birds or to adopt a regular eight-week cycle of worm treatments.

Heavily fouled and muddied areas outside the pop-holes of free-range houses are a hot-bed for disease, say vets. Although producers can be meticulous in internal cleaning of houses in-between batches of birds, not enough thought is given to the cleanliness of the ground outside the houses when birds have to contend with wet weather during the higher temperatures of summer, he said.

“It may not have seemed hot, but because summer temperatures are higher than winter, the environmental conditions are ideal for disease build-up when ground surfaces never dry out. The faeces on areas close to buildings must be dried by ultraviolet light to break them down if they stay wet they remain a source of contamination to birds.

“Thoroughly cleaning a poultry house inside will render the effort null and void in terms of disease control if pullets are then introduced without attempting to decontaminate the areas immediately outside the sheds. The new birds will be at risk from picking up infection from the old hens,” said Mr Clark.

Grates outside pop-holes, improved drainage and introducing paddock rotation to prevent birds being forced to use wet and fouled ground will go some way towards reducing the build-up of disease in wet and muddy outside areas. Using stone or gravel in areas around the pop-holes – and scraping off and replacing the top few inches with clean material inbetween batches- may be an option some producers need to adopt if wet summer months become the norm.

“Mud and faeces are a fatal combination in terms of their spread of disease and while it’s difficult to eliminate them in wet weather, this may be one of the future management challenges facing free-range producers,” said Mr Clark.