Free range birds benefit from underfloor heating

When Stuart Cole built his first chicken houses at Menchine Farm, Witheridge, Devon, he was convinced that there had to be a better way to heat them. Three years on, he is setting a new standard for poultry production with two new sheds featuring under-floor heating and large polycarbonate windows.

“Within a few months of building the other (four conventionally heated) sheds I figured there must be a better way than heating the air above the chicks and then using yet more energy to push the warmth down to their level,” he says. “But at that time the technology to do it differently just wasn’t available.”

However, a trip to a poultry producer in Chesterfield [Poultry World, p34, November 2007] revealed the potential for under-floor , and in November 2008 Mr Cole became only the second producer in the country to install the new technology.

His two new 476sq m (5124sq ft) sheds each house 5750 free-range birds, bringing the whole farm total to 34,500 chickens reared for local processor 2 Sisters Willand (Lloyd Maunder). Each shed floor is under-laid with 1600m (5249 ft) of water pipe spaced at 30cm (about 1ft) intervals and connected to two 18kW gas-fired boilers.

Hot water is pumped around the pipes, heating the floor to the required temperature. “It’s a far more efficient way of heating,” says Mr Cole. “And keeping the chicks and the litter they’re on warm is crucial to successful poultry rearing.”

Day-old chicks need a temperature of 33C at floor level to survive. Traditional 75kW air heaters heat the air to at least 40C, to make up for the warmth lost before it reaches floor level. But the new under-floor system maintains an optimum temperature right where the chicks are, reducing in a controlled manner as they grow.

Mr Cole has also installed energy-saving lighting triggered by a sensor and polycarbonate vent windows which flood the houses with natural daylight. “In the summer the lights will hardly ever be on,” he says. The windows represent 10% of the total floor area – significantly higher than the 3% required by the RSPCA’s Freedom Food standards.

“The windows give a completely different feeling when you go into the sheds.” The litter is also much drier than in the conventional sheds, due to the warm floor, resulting in a massive reduction in ammonia. Combined with the cooler air temperature at head height, the new sheds offer a far more pleasant environment for birds and humans alike, he says.

“The early signs are that more of the birds range more of the time and they tend to go further,” says Mr Cole. “I can only put that down to the fact that they’re used to sunlight from day one.” At 50 days the chickens in the new shed weighed 1.96kg – 4% heavier than chicks from the same batch in the older housing. “It’s worked out better than I could have expected to date.”

The system cost an extra £10,000 per house to install, but should cut electricity and gas bills by 40-50%. Mr Cole reckons it will pay for itself in six or seven years, with the added bonus of requiring 50% less straw bedding.

“We usually put quite a lot of bedding in to keep the chicks off the cold floor, but it stops the heat from getting through. It was panic stations on the first day as I had to scrape the litter back off.”

Mr Cole has also fitted large barn doors at either end of the shed, which can be opened to provide a through draught in hot weather. He will soon be installing polycarbonate windows in his older houses, as well as ample wooden perches which are proving a hit in the new sheds.

Not content with leading the way with his under-floor heating, Mr Cole is also aiming to become one of the country’s first carbon neutral poultry producers.

With a steady wind speed of 6m/second, he plans to erect a wind turbine to generate his own electricity. He also wants to install a ground source heat pump to replace the gas boilers and grow his own oilseed rape to process into biodiesel for the tractors. “We like to think we’re growing the best chicken we can.”

Andrew Maunder, commercial director at 2 Sisters Willand, says he is very proud of Mr Cole’s initiative. “He’s blazing a trail we hope other farmers will follow.

“It’s important in a credit crunch that we don’t desert producers like Stuart who have pioneered so much. Free-range chicken is still a very cheap meat when you look at a portion cost, and it’s important that consumers stick to their core values, buy British, and buy local.”