That makes sense
PUBLISHED: 16:44 10 March 2014
Chickens have great vision and hearing to keep them safe from predators. Charlotte Popescu takes a look at their senses
Scientific research tells us that chickens have excellent vision and I can certainly back this up as a result of watching my hens during the day: dashing after flying insects; seeing me through the windows or door even when they’re way up the garden; and spotting flying predators well before I do. With their eyes placed on opposite sides of their heads they have a panoramic vision of 300° compared to a human’s forward facing vision of 180°. Chickens have a binocular vision (this is the field of view seen by both eyes) of only 26° whilst humans have 120°. Unlike humans though a chicken’s eyeball is stationery so it has to move its head to follow objects.
Chickens seem to like bright colours. Red and blue are favourites, hence a cockerel with his red comb is very desirable. Drinkers are often coloured red to make them more attractive. The human retina has three cones sensitive to red, blue and green wavelengths. Chickens however have four cones in their retina with the extra one being for UV or ultraviolet vision. This extra sensitivity to colour, which is found in all birds, may have evolved to help females find mates; cockerels do often have very colourful feathers compared to their female counterparts to make them extra attractive. The ultraviolet vision also probably makes red and other coloured fruit easier to locate and this is especially important for wild birds. Certainly my hens are able to leap up and eat all my low-growing raspberries and snatch any ripe strawberries or blueberries through my protective netting. And when I am picking raspberries and drop one, it is gobbled up before I can even find out where it is! It is difficult to imagine how the colours the chicken sees differ to how we see them but I guess they must see everything with an extra brightness – I think the colours they see must positively glow!
Chickens are blessed with a third eyelid. Apart from the two eyelids that come together when a chicken shuts its eyes there is a nictitating, translucent membrane which is located next to the eyeball and slides from front to back. This membrane’s function is to moisten, clean and protect the eye. It is particularly useful when dust bathing as it will protect the eye from dirt. Sometimes when you take a photo of your favourite hen its eyes will appear hazy or blurred because the membrane is being used – it’s just one more hindrance to getting the perfect picture.
Research has revealed that chickens possess something called lateralisation which means they use their left and right eyes for different tasks. Day old chicks use their right eye for close up activities such as feeding and their left eye to look out for potential predators or other distant objects. This visual lateralisation materialises when the chick is still in the shell. From the 17th day of incubation the eyes respond to light. It has been discovered that they turn their heads to the left so that only the right eye is exposed to light through the shell and membrane.
You will probably have noticed that your hens have rather poor night vision which is why they usually put themselves to bed before dusk descends and why they need protection against predators at night.
Chickens have a very good sense of hearing. Their ears are located near to their eyes but there are no pinnae or exterior ears showing. A few feathers cover the ear opening and you can also see what we call the ear lobe which is usually red or white. Chickens are capable of making lots of different noises when communicating with each other. Hens can hear their chicks cheeping in their shells and mother hens constantly call their chicks to food. Cockerels and hens will always alert each other through cackling to any dangers or threats from predators that they see. They will respond to human voices and can be taught to come when you call them. So keep chatting to your hens; you never know what they might understand!
In general chickens, especially the light breeds, don’t really like being touched but regularly picking your hens up and stroking them is not a bad idea if you want calm, docile birds. Chickens are able to be hypnotised by gently rocking them back and forwards. Stroking a hen gently on the neck seems to calm a squawking bird and may even immobilise her for a short period. You can try sorting out an aggressive cockerel by carrying him around and stroking him (advisable to wear gloves); you will be showing him who is master and he may well lose any aggressive attitude he has had towards you. Touching the back of a hen may cause it to respond with a sexual crouch (ie ready to be mounted by a cockerel even if you don’t actually have one) especially if it is quite a submissive hen. Regarding touching each other, families of chicks like to relax together often bunched up, giving them extra warmth and a sense of protection. Fully grown hens don’t mind touching each other when dust or sun bathing and will often share a nest box when laying eggs. They are social animals and do seem to like each other’s company. They will roost together on the perch often touching each other for warmth and comfort. Chickens obviously use their beaks for picking up food and foraging in the earth and leaves. Caged hens, which become available for rescue, have usually been debeaked which means they lose the tip of the beak; this is thought to be sensitive and a useful sharp tool when it comes to grabbing those tasty worms and grubs.
TASTE AND SMELL
Chickens have far less taste buds than we do, around 340 as opposed to our 10,000. This implies that they can taste but not that much is known about their sense of taste. There are foods that chickens will not accept, especially anything too salty or spicy. An old fashioned method of curing egg eating was to insert some mustard into an empty shell and this would invariably work! A chicken’s sense of smell is not thought to be very good. On the whole anything that is mouldy or sour is rejected and my hens don’t eat strong smelling herbs such as rosemary, sage, mint or lavender. They don’t like carrot tops or carrots which are also quite pungent. They don’t eat the rocket or oriental mustard leaves that I grow as these are very strong tasting. Chickens don’t tend to touch poisonous plants so must be able to make this decision based on smell and possibly texture. My hens tend to eat windfall apples that have gone brown so there must be something about these that tastes good. Chickens do not like to drink hot water that is above approximately 32°C (or water than is warmer than their body temperature) but will happily drink freezing water and I have noticed mine like to eat snow and crushed pieces of ice.
So all in all chickens’ best assets are their eyes and ears originally designed to help keep them safe in the wild.