Warm and wet winter conditions are far from ideal for free-range chickens.
The range becomes muddy, litter gets wet, and parasites and diseases abound. So what can producers do to overcome these difficulties?
According to Richard Jackson, clinical director at St David’s Poultry Team, the key is to optimise intestinal health.
This ensures energy and protein can be absorbed and assimilated, thereby maximising production and the bird’s immune system.
“Maintaining optimum intestinal health can be a challenge at the best of times, however this winter requires a really proactive approach for best chances of success,” he says.
The biggest challenge tends to come upon arrival at the farm – the stresses of transport, a change in environment, water quality and diet, and likely exposure to new diseases, all impact on the bird’s intestinal health.
Early warning signs of dysfunction include finding a number of frothy yellow droppings, says Mr Jackson.
Feed and water intake will also drop, weight gain will slow, and eggs may be smaller than expected, with poor quality shells.
Producers should therefore try to minimise the stress on pullets by limiting the disease challenges through careful terminal cleaning and range management.
Of course, in a season like this, good range management can be hard. Cold winters have the benefit of reducing disease levels and internal parasites, whereas this year’s mild and wet weather is ideal for pathogens to flourish.
The main worms to look out for are capillaria, ascaridia and heterakis, says Mr Jackson.
“Both capillaria and ascaridia worms can irritate the lining of the intestine leading to poor nutrient absorption and general bacterial enteritis.”
Heterakis worms are not harmful in their own right, but can carry blackhead, a disease which can be deadly to layers.
“Worm burdens can also depress appetite, which in itself can affect the balance of good and bad bacteria in the intestine.”
Producers should ideally take faecal egg counts every six to eight weeks, and give a licensed wormer such as Flubendazole or Fenbendazole if required.
“It’s essential to administer the full course to maximise efficacy and reduce the risk of anthelmintic resistance building up.”
Terminal hygiene is crucial in the management of worms, and it’s important to use a Defra-approved disinfectant to destroy worm eggs, says Mr Jackson.
“Not all disinfectants will destroy worm eggs, so always check with your supplier.”
Range and water management
Although cleaning and disinfecting the shed is relatively straightforward, managing the range can be more difficult.
Sunlight is a farmer’s greatest ally in destroying bacteria, viruses and parasites, but that has been in short supply this winter.
“Ensure grass is kept short and that tree cover never completely stops light reaching the soil’s surface. Applying agricultural lime at turnaround can also help destroy worm eggs and other pathogens.”
Farmers should ensure that the range is well-drained, as standing water can harbour bacteria that can cause diarrhoea.
Installing French drains outside the pop holes, and perhaps an area of hard standing around the shed, will reduce tracking of wet mud back into the house, says Mr Jackson.
“If possible, create a paddock system so you can give the range a rest.”
Drinking water is similarly important, he warns.
“The average layer drinks 200ml of water a day, and bacteria in drinking water are usually harmful.”
With borehole water it’s essential to have water treatment systems in place that are monitored every six months and serviced regularly. However, bacteria can soon build up, even in mains water.
“Vitamins and medications added to the water can contain substances that aid bacterial growth and biofilm formation,” says Mr Jackson.
“It’s vital that water is regularly sanitised, ideally with a stabilised hydrogen peroxide-based sanitiser to help destroy biofilm.”
Producers should also flush drinker lines weekly to ensure water at the end of the lines is replaced as it can become stagnant and disease-laden.
Another aspect to consider is the water mineral content.
“Some minerals are a good thing, but excessive levels of manganese can lead to intestinal irritation, while too much iron can encourage bacterial growth and biofilm.”
Even where a farmer’s range management, terminal hygiene and water quality is excellent, birds can still suffer from intestinal upsets simply through the stress of laying, says Mr Jackson.
Producers should therefore consider bolstering intestinal health with feed or water additives.
“One option is probiotics. There are two broad types available – those with ‘good’ bacteria found in the intestine of healthy chickens, and those with bacteria that produce substances to destroy harmful bacteria.”
Products that contain lactobacillus should be given early in life or after antibiotic treatment. “They work by displacing harmful bacteria and leaving less room for them in the gut,” says Mr Jackson.
Those that destroy harmful bacteria include Bacillus subtilis, which inhibits Clostridium perfringens – the most common harmful bacteria found in the gut.
Another option is to use organic acids.
These make the gut more acidic, encouraging the growth of ‘good’ bacteria which prefer an acidic environment, while discouraging harmful bacteria which prefer a more alkaline environment.
“Organic acids also encourage development of villi – microscopic finger-like projections in the gut which increase its surface area,” says Mr Jackson.
“Greater villi development boosts nutrient absorption, which directly improves performance.”
However, it is important that organic acids are protected so that they reach the desired region of the intestine intact, he adds.
Other beneficial additives include Mannan oligosaccharides (MOS).
“These yeast walls bind to the surface of harmful bacteria, meaning they cannot attach to the gut and so are passed out in the droppings before they can cause harm.”
Whatever the weather, producers need to be as proactive as possible to optimise bird health, warns Mr Jackson.
“There is no silver bullet, especially in a difficult winter like this. It’s all about meticulous attention to detail in the shed and on the range, with the additional support of dietary supplements at times of stress or throughout the laying period to boost bird health.”