A chicken’s feathers perform a variety of important functions. Poultry vet Victoria Roberts reports

Feathers help to define a breed or type of chicken and are used for insulation, temperature regulation, behaviour, touch (sensitive hair-like feathers) and incubation. A healthy hen will have shiny, clean feathers, all of them present, so a lack of feathers is a hazard to keeping warm – evident in ex-bats at first rescue. In hot weather, keeping chickens cool is more challenging. Shade must be provided; hot hens will hold their wings out and pant. Spraying with water may be needed.

Feathers are composed of keratin (similar to hair, nails, beak and claws) with the addition of pigment and patterns which are genetically determined. Males and females have different shaped feathers; the male feathers are pointed and very shiny on his back, the female feathers remain round-ended all their lives. An eight- week-old chick will have rounded feathers and then the male shaped ones begin to appear between the shoulder blades, so most breeds (not Silkies) can be sexed by this change of shape from about 10 weeks. You are thus able to check the shape of the back feathers of all purchases to avoid inadvertently acquiring cockerels.

In order to keep her feathers clean, a hen will dust bathe, preferably communally, rolling around and flicking dust over herself and then giving a good shake to dislodge dirt and any parasites. Preening is the daily activity of a hen drawing a feather through her beak in order to re-zip the barbs (think Velcro) which maintains the feather’s waterproof properties (again, not Silkies). She also rubs her beak on her preen gland (just above the tail) to put a little oil on her feathers when she preens. This oil contains inactive vitamin D which is changed to active vitamin D when she sunbathes, then she preens again and ingests it (important for good muscle and bone health). Commercial hen feed tends to have this vitamin added in case of a lack of sunshine.

Feathers have to work hard to do their job of insulation well and are replaced generally every autumn since they not only fade their colour over time, but wear due to constant abrasion – a fresh set looks very smart. When a hen is ready to moult, she still needs good nutrition, otherwise the feathers will grow poorly and be weak. Moulting should take around three weeks but if nutrition is not sufficient it can take longer as moulting is a very energy-expensive activity. A seaweed supplement will help at this stage as the iodine in seaweed supports strong keratin growth. A new feather pushes out the old feather from the follicle with the shaft of the new feather filled with blood so that its growth is optimised, the blood being resorbed once the feather is fully grown – remember to look for a shaft clear of blood if clipping wing feathers. If nutrition is interrupted during the moult, fret marks (lines at right angles to the shaft) can appear on tail or wing feathers which stay until the next moult.

A hen may peck the feathers of the rest of the flock, and if left unchecked this could lead to cannibalism particularly if blood is drawn – the culprit is usually the one with a complete coat. This aggression can be caused by overheating, whether through a poorly ventilated hut or the feeding of maize in warm weather, so keep to whole wheat as a treat in the summer months and check the ventilation. Some hens seem to get stuck in a moult, particularly ex-bats on their rear end and abdomen. Skin that is normally covered by feathers tends to become red due to exposure to the elements. This is not sore, just a reaction and when the feathers grow back (helped by the seaweed supplement) the skin colour returns to normal. Anyone who has seen Transylvanian Naked Necks will realise that where the skin is bare (they have half the normal amount of feathers), it is always red.

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