Litter and air quality: ammonia, humidity and feet

What litter is for

Litter is not just a floor covering. It has three functions:

• Absorbing moisture (spilt water, droppings).
• Diluting droppings, so that the birds are in as little contact with them as possible.
• Insulating the birds from the cold floor, especially at the start.

The choice of material matters (lesson 2 of this track for depths). A few warnings: sawdust is often damp, goes mouldy easily and chicks may eat it, which can cause aspergillosis; hardwood shavings may contain toxic tannins and splinters that injure the crop; coarsely chopped straw tends to cake in the first weeks; peanut hulls also cake but remain manageable. Rice hulls are a good, inexpensive choice.

Source: Cobb.

Litter that is too wet is costly

Above about 35% moisture, litter causes welfare and health problems. The hand test (lesson 2) is enough to monitor it: a squeezed handful should stick slightly, then break up when dropped on the floor. If it stays in a ball, even when dropped, it is too wet. If it does not stick at all, it is very dry.

• Breast blisters (keel) and skin burns.
• Foot pad burns (pododermatitis): the soles of the feet become covered in scabs and sores.
• Condemnations and downgrades at the processing plant.
• More ammonia in the air.

Source: Cobb.

Ammonia and the other air benchmarks

Ammonia comes from droppings, especially when the litter is wet. Always assess it at bird height, not at head height: crouch down. If the smell stings your nose or eyes at that level, the air is already bad.

• Effects of ammonia: foot pad and eye burns, breast blisters, skin irritation, lower weights, poor uniformity, more disease, and even blindness.
• Chicks are the most sensitive: an ammonia level that hardly affects a 7-week-old bird can reduce the growth of a 7-day-old chick by 20%.

Source: Cobb.

Carbon monoxide comes from heaters that burn gas or charcoal: the air must be renewed as soon as the heating is switched on, even before the chicks arrive.

Ventilate even when it is hot

A common mistake is to believe that in a hot climate there is no need to ventilate in the morning or at night. At every age, ventilation removes heat, water vapour and carbon dioxide. In the first week, when the house is closed up to keep the heat in, carbon dioxide rises quickly: it must never exceed 3,000 ppm.

Source: Cobb. In the morning, open the leeward side first; before 14 days, renew the air without any draught at chick level (lessons 3 and 5 of this track).

Humidity also changes the temperature to aim for: when the relative humidity is above the benchmarks for the age, you can lower the temperature by 0.5 to 1 °C; when it is below, raise it by 0.5 to 1 °C. The birds remain the best thermometer.

Finding the cause of wet litter

• Under the drinkers: wet litter = drinkers too low, water pressure too high or drinker not ballasted. Very dry litter under the drinkers = pressure possibly too low.
• Bell drinkers: lip at back height, always ballasted to limit spillage, at least 0.6 cm of rim per bird. Water level 0.5 cm from the lip on day one, then lowered gradually after 7 days to about 1.25 cm (the depth of a thumbnail).
• Nipples: a droplet hanging from the end, never a leak; the bird drinks with its feet flat, without standing on its toes.
• Misting: never above 70% humidity, nor below 28 °C; if the mist from two nozzles merges, there is too much water.
• Too many birds per m²: the litter can no longer cope.

Source: Cobb.