Dermatitis in broilers is caused by a combination of moisture and chemical irritants like ammonia in the litter material during natural decomposition. These conditions affect areas of the skin greatly exposed, like the feet, hocks and breast. In most cases, they develop inflammatory reactions in the skin and even ulcers. In foot pads, these lesions are observed as early as four to six days of age but are most commonly seen around 12 days. They can heal but most frequently augment, causing blemishes to feet and breast at processing.

Footpad dermatitis (FPD) is also called paw burns, ammonia burns or pododermatitis. This disease has gained importance due to the value of chicken feet as a profitable export item to Asian markets. Nowadays, broiler feet have become one of the most profitable parts of the carcass for export. Additionally, FPD has become a welfare concern since it affects broiler ability to walk and reduces feed intake and growth. The evaluation of FPD incidence is now part of many welfare audits. It is desirable to have less than 30 per cent of the flock with feet lesions but it is difficult to achieve this goal.

This newsletter has the objective of listing a series of recommendations to reduce incidence of FPD and other dermatitis problems at farm level. The main objective in controlling FPD and all dermatitis is to avoid litter wetness and production of ammonia or other irritant compounds from the litter. This process starts even before chickens are placed.

Management between Flocks

When it is necessary to reuse the litter, after removing the caked material, allow the litter base to dry before chicks are placed. Running fans during the day can help to dry out the litter faster.

Windrowing litter has produced better results in paw quality of the next broiler flock than just caking out and/or doing a complete clean-out of the house.

After removing the litter or caked material, make sure to keep at least three inches of litter absorbing material across the entire house. Mortar sand and ground door filler revealed the lowest incidence of FPD in all trials (Bilgili et al., 2009). Independently of the litter material selected, use a small particle size of less than one inch.

If necessary, spread new bedding material evenly. Floors must be smooth and level. Uneven floors make constant height adjustment and water line pressure regulation very difficult. A gradual grade of no more than four inches of drop from one end to the other is acceptable.

Ammonia acidification may help to reduce bacteria and ammonia production during the first two or three weeks. The effects of litter acidifiers depend on doses. Rates of 120 lbs of acidifier or more per 1,000 square feet in the brooding chamber or the whole house are necessary to observe substantial reductions in FPD.

Before placement, clean, flush with high-pressure (15 to 30 pounds per square inch, psi), and sanitise drinker systems to avoid built up of mineral residues and biofilm that can cause leaky nipples.

Pre-warm the house to reduce litter moisture, especially when litter depth is low (less than three inches). Litter temperature should be 28 to 30°C at chicken arrival.

House Management during the Flock

Manage drinker lines according to manufacturer's guidelines to prevent leaks that add moisture to the litter. Broilers spend the majority of their time in this area and consequently, it is the most critical house section for moisture control. Check filters weekly and replace them as soon as they collect significant amounts of debris. In most systems, proper pressure is critical during grow-out, and it is important that the water columns in the riser tubes be clearly visible. Keep the riser tubes clean.

Maintain appropriate water pressure and keep drinker lines level and uniform with appropriate height according to bird height to avoid water wastage that will add moisture to litter underneath the water lines. Try to use the lowest water pressure recommended by the manufacturer. Low water line pressure can reduce litter moisture and FPD prevalence but monitor water intake because if the water pressure is too low, broilers can reduce water and feed intake, and growth.

Unleveled and uneven height between the lines cause that they are used for broilers more in some areas than in others, occasioning uneven distribution of moisture in the litter that is more difficult to dry. Uneven distribution of the flock caused by lighting problems, or uncomfortable temperatures or uneven air flow in some areas may cause similar negative effects on litter moisture and FPD prevalence.

In the brooding phase, give more space to the flock around nine days. Avoid overcrowding in the brooding area. Lesions in the feet skin caused in the first and second weeks of age may become infected and develop FPD.

Avoid condensation of moisture by improving house insulation and negative pressure, reducing uncontrolled air entries, and doing maintenance and calibration of electronic sensors and fans. Condensation occurs mainly in the side walls. Daily observation of these areas and use of hygrometer can help to keep relative humidity between 50 and 70 per cent, and litter humidity not higher than 35 per cent. Condensation is more common when the outside temperature is low, and relative humidity is high (winter and early spring conditions, or early morning year-around). Consequently, winter time and low frequency of ventilation increase chances to have condensation especially during brooding when inside house temperature is higher than outside environmental temperatures.

Monitor daily water consumption of the flock to establish variations that can indicate problems. Broilers should drink two to three times the amount of feed that they eat. If the flock is drinking more than expected, you should double-check health conditions, water quality, litter quality and house temperatures. Minerals in the water may increase water intake, cause enteritis problems, flushing and wet litter. Water can be treated to minimise the content of undesired minerals. Uncalibrated electronic sensors may cause that house temperatures to rise higher than programmed in the electronic house controller.

Hotter temperatures influence more water intake, wetter droppings and wetter litter. Excess litter moisture is difficult to dry out with the normal running time of fans. Similar problems can happen during the summer or on hot days if the house gets hotter than planned; there are water leakages from drinker lines, foggers or water sprinklers; and if fan time is not increased to account for this extra and unexpected house humidity.

Research results indicate that these recommendations will have positive effects on paw quality and general broiler flock performance.

Reference

Bilgili, S.F., J.B. Hess, J.P. Blake, K.S. Macklin, B. Saenmahayak and J.L. Sibbley. 2009. Influence of bedding material on footpad dermatitis in broiler chickens. J. Appl. Poult. Res. 18:583-589.

October 2010