Measuring Animal Welfare with Paw Health

By November 14, 2018News, PLT

In a recent article, we discussed how moisture is the number one variable producers can manage to help control ammonia production, thereby boosting bird performance. However, performance gains are just the beginning. When identifying ways to improve animal welfare, moisture management and ammonia control play a pivotal role for many reasons—one being their impact on footpad health.

Footpad dermatitis, also referred to as paw lesions, requires moisture at the litter surface and ammonia in the litter bed to develop. However, if houses have low or no ammonia but damp litter, birds can still have a high number of paw lesions since the litter provides a medium for liquid ammonia to come in contact with paws. Litter acts as a sponge in a broiler house—absorbing moisture and diluting the fecal material of the flock. Like a sponge, a thicker litter base will retain more moisture, dissipating it away from the litter’s surface. As litter depth increases, moisture decreases and paw quality improves.

pH Matters by Jones Hamilton

Paw Lesion Development: The Process

Standing on wet litter causes birds’ footpads to soften, making them more prone to damage. The litter sticks to their paws, and then the ammonia starts to erode the skin. The abrasiveness of certain substrates can also incite lesions, making it vital to use bedding substrates or a mix of substrates that are soft and mailable that wick moisture away.

The severity of the moisture-laden litter, or cake, plays a predominant role in the development and severity of lesions. Higher moisture content results in a greater degree of lesions, especially if the wet litter has a significant number of sticky droppings. Conversely, the fluffy, dry litter found in houses after windrowing or decaking can also lead to lesions since the bird’s foot is immersed in the litter base. Birds are most at risk during the first three to four days, or until the fluffy litter compacts.

Paw lesions become visible quickly—within seven to 10 days—and will worsen over time. This predictable timeline serves as a valuable tool for identifying brooding challenges.

Maximum ammonia volatilization occurs at approximately 42% litter moisture with temperatures of 75°F; at 95°F, maximum generation occurs near 46% litter moisture. At 95°F and 20% litter moisture content, ammonia volatility is nearly doubled compared to the same moisture content at 75°F.

With increased scrutiny and publish pressure to maintain precise welfare standards, the importance of maintaining healthy paws cannot be underestimated.

Focus on Paw Health: Welfare and Profitability

Arguably the most important reason to focus on paw health is the fact that it used as an indicator of bird welfare. With increased scrutiny and publish pressure to maintain precise welfare standards, the importance of maintaining healthy paws cannot be underestimated.

In addition, the profitability of paw has skyrocketed in recent decades. What was once largely thought of as disposal, has become the third most profitable part of the chicken behind the breast and wing; and there is significant room for increased profitability. Some estimates put U.S. losses due to downgraded or condemned paws at $250-300 million annually. While there are a variety of reasons for condemned paws, nearly 99% are due to paw lesions.

Slide the arrows to see the clear difference between a healthy Grade A Paw and a downgraded paw.

Timing is Everything

While paw lesions can occur in broilers at any age, producers must consider the timing of lesion development and what intervention measures can still be effective in mitigating their impact. If caught early in baby chicks, there might still be time to remedy house conditions and improve paw health. For market-age birds, however, there is often little to be done prior to catch. It is more effective to focus on improving the litter condition during downtime for the next flock.

Precise House Management for Healthier Paws

Maintaining healthy paws for increased profitability and improved welfare requires careful management of the house environment and litter condition.

Ventilate to maintain a relative humidity (RH) of 50-70%.

One study showed that raising birds at a 45% RH compared to a 75% RH reduced paw lesions substantially. Birds in the 75% RH group had three times the ammonia burns on the feet and the severity of the lesions was greater than those birds raised in the 45% RH group.

Neutralize ammonia with a litter acidifier.

Applying PLT eliminates ammonia and its risk to paw health. Applying extra PLT in damp areas may be necessary to neutralize the ammonia in solution (water). If paw lesions are seen in young chicks, adjust ventilation and consider applying PLT mid-flock.

Manage drinkers to prevent excess moisture.

Caked litter is most commonly seen under drinker lines and along sidewalls. Manager drinkers to ensure proper height and pressure, and regularly flush and sanitize lines to reduce water leakage.

Manage bird density.

Bird density and litter moisture are directly correlated. As density increases, so does water consumption. Considering that 80% of the water birds drink ends up on the floor, the impact on paws can be significant. Controlling density and using migration fences to ensure birds are more evenly spaced out throughout the house enables easier moisture control.

Dr. Tom Tabler, Jessica Wells, Dr. Wei Zhai. “What Causes Footpad Dermatitis” Mississippi State University Extension Service. 2013

Weaver, W.D. and R. Meuerhof. “The effect of different levels of relative humidity and air movement on litter conditions, ammonia levels, growth and carcass quality for broiler chickens.” Poultry Science 70:746-755, 1991.

  1. Czarick, B. Fairchild. Minimizing Footpad Dermatitis and Maintaining Good Paw Quality. Poultry Housing Tips. University of Georgia. 2011.

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