AnusmitaBaishya*, Utsav Surati, Priyanka Patoliya
PhD scholar (LPM), NDRI, Karnal, Haryana-132001
PhD scholar (AGB), NDRI, Karnal, Haryana-132001
PhD scholar (LPM), NDRI, Karnal, Haryana-132001
Abstract
The bird’s natural behaviour in the wild is perching. In order to protect themselves from predators at night, hens in particular that are not kept (such as feral chickens in Asia) will roost off the ground. The bird can assume a natural grasp with its feet while sleeping by placing a branch or similar structure nearby that is the right size. The domesticated chicken is a relative of Southeast Asian jungle birds, which live in forested areas in their natural habitat. Chickens of today still feel the need to roost, especially at night. Perches in chicken housing can enhance the natural behaviour of the birds. Perches are extensively used for laying chickens. Due to their increased weight, broilers (chickens raised for meat) rarely need perches. The majority of waterfowl don’t use perches, however Muscovy ducks prefer to roost, just like chickens do. Perches are not required, but research has shown that hens enjoy having them in their home. Domesticated fowl still have the impulse to perch, and in contemporary intensive or extensive commercial egg-laying systems, hens will perch if given a surface to grab onto. This impulse to perch can induce birds to perch on inappropriate surfaces, such as interior roof supports, wires, and cables, in poorly built systems, and this could result in the bird hurting itself.
Benefits of using perches:
Giving laying hens perches is a good technique to lessen stress in them, as well as certain injuries and cannibalism. Hens lower in the pecking order use the perches during the day to avoid being picked on by more powerful hens. This capacity to flee lessens the likelihood of cannibalism and injuries to the head and neck brought on by aggressive pecking and severe feather pecking. However, it’s crucial to make sure that perches are sufficiently apart from one another to prevent birds on lower perches from pecking the cloaca or bellies of birds above. The more dominant hens take the upper perches when the hens collectively perch at night. Because they allow birds to keep off the ground, especially at night, perches can also help with waste management. As a result, dung tends to collect beneath the roost area, keeping the rest of the bedding in the house cleaner. At different times of the day, birds of different dominance ranks (or “peck orders”) may use perches. Submissive birds can use the perch as a haven from dominating birds during the light hours. The dominating birds, however, will take up residence on the higher perches at night. While birds in a commercial laying house shouldn’t be in danger from predators at night, letting the birds carry out this natural task is one approach to lessen stress in the laying hen.
Perch design and construction:
Perch shape, diameter and height: The recommended diameter for a perch is between 3 and 5 cm and a rounded profile with a flattened top appears to be most suitable. There must be no sharp edges. There needs to be sufficient space either side of the perch to allow hens to grip without there being a risk of the claw becoming trapped. The recommended vertical height for the first perch is a minimum of 70 cm from the surface to which it is secured to reduce the likelihood of hens on the floor from pecking birds above, however hens show preferences for higher perches (90 cm or more) at night time. A variety of perch heights should therefore be given. Perches should neither be spaced too far from one another (vertically or horizontally), nor at too steep an angle, to encourage safe landings: vertical distances < 50 cm 3, horizontal distances < 75 cm 3,4,5,6 and angles < 45° 3,7,8 can help reduce poor landings and keel bone damage. If the perches are positioned at too great a vertical distance from each other, or too high from the floor surface, it is more likely that birds will misjudge their landing and collide with the perch/floor injuring their keel bone in particular. Also, because birds find it more difficult to land safely on perches when descending (as opposed to flying up to the perch) consideration needs to be given to providing safe and easy access down from higher perches. The provision of ramps can improve the safe descent of hens from the top levels to the floor.
Perch material: Perches can be made from various materials and there is no conclusive evidence as to the best material to use from a welfare perspective. Wood, metal, and plastic can all be used to construct perches. There is some evidence that, when clean and/or frequently used, plastic and metal perches present a slippery surface which birds may find more difficult to use (compared with wood, for example). Perches coated with rubber or another soft material support a stable footing of hens. In addition, a soft rubber surface can help to reduce keel bone damage by buffering pressure peaks on the keel bone while resting and landing. Whichever material is used; consideration needs to be given to the suitability of the material as a harbourage for parasites such as red mite or as a reservoir for bacteria or viruses. In essence the ideal perch would have a non-slippery and soft surface but would not provide any crevices or voids that red mite could access and it would be easily cleaned and disinfected after depopulation of the hen house.
Perch position: Birds will tend to defecate from the perches so positioning the perch over the slatted area or similar will help control the build-up faeces in the house. Perches must not be mounted above the litter area. For the same reason, where possible, the perches should not be placed in such a way that the birds could contaminate feed or water supply systems with their faeces. Similarly, perches should not be positioned directly over one another if possible, to prevent birds from soiling one another. The angle between perches should be less than 45 degrees, if possible. To limit the risk of birds misjudging their landing and injuring themselves the higher perches should be positioned so that they can be reached either from lower perches or from other furniture such as nest boxes. Perches, if poorly constructed can be barriers to move around the house. Consideration needs to be given when installing perches not only to the requirements of the bird but also to those of the stock workers and catching crew. In particular care should be taken that the perches do not pose a barrier to the nest boxes. This can be achieved by ensuring that the lowest perches are sufficiently high above the ground to allow birds to walk underneath them. In multi-tier aviaries perches often are mounted within the tiers. In such cases the distance between the perches and the roof of the above tier should be more than 20 cm. If perches can be readily removed from the house this should make the catching and cleaning processes in particular easier however this may not be feasible. If the perches are permanent fixtures care needs to be taken when designing and setting the perches to ensure that they do not pose a barrier that birds will collide with when being driven for the purposes of catching.
Guidance of using perches: According to organic standards, perches should be of minimum 15cm per hen (about 6 inches per hen) of perch space under regular standards and 18cm per hen (about 7 inches per hen). Moreover, there must be a minimum of 30cm (about 12 inches) of horizontal space between perches and 20cm (about 8 inches) between a perch and the wall. Also, the perches cannot have sharp edges. If you plan to include perches in your poultry housing, you should introduce the perches to the flock when the birds are still young. Rearing chickens without early access to perches has been shown to impair their ability to use the perches as adults. Location and placement of perches are important. Locate perches in an area of the house where they will not interfere with the daily care of the birds, including feeding, watering, and egg gathering. Also, the roosts should be removable to allow you to clean out the manure that accumulates under them. Place the lowest perch about 3 feet off the floor to minimize the opportunity for other chickens to feather peck a chicken using this roost. Consider the vertical distance between perches too. If the vertical distance between perches is too large, it is more likely that the chickens will misjudge their landings and collide with perches, thereby injuring their keels. Also, chickens find it difficult to land safely on perches when jumping down, so ensure that there is sufficient floor space to allow the chickens to land safely when leaving the higher perches.
Perch shapes and the materials used to make perches vary. Europeans typically use round iron tubes for perches to minimize infestations of red mites (Dermanyssusgallinae). However, these perches are associated with a higher risk of keel deformations. Some flock owners have used plastic perches with mushroom shapes, but red mites hide during the day in the areas where these perches are connected to each other. Wooden perches also are very sensitive to red mites. In Europe, the presence of red mites is a more significant problem for poultry producers than keel deformations, so European producers prefer the iron tube perches. If red mites are not a concern, wooden perches are the best option because more layers use perches if the perches are square rather than round.
Risk of using perches: Domesticated chickens are considerably heavier than the mature jungle fowl, and the modern chicken has a relatively smaller wing surface area. These traits make the modern chicken an awkward flier. As a result, often an increase in keel injuries exists in chickens with access to perches, due to misjudged landings. In addition, high egg output demineralises the skeleton, making the keel bone particularly susceptible to deformations when applying pressure on it during perching and fractures during clumsy landings. These factors may account for the tendency of hens in alternative systems to damage their keel bone. To minimise the risk of birds injuring themselves on perches and to maximise the use of perches in commercial hen houses, a number of factors need to be taken into account. However, prior to hens coming into the house it should be emphasised that rearing pullets with perches is known to train them in the use of perches and to increase their use during lay. Research from 2010 and 2011 showed that the use of perches is associated with a higher incidence of skeletal damage (such as bone fractures and keel deformations) and fat pad lesions.
Requirement of perch space:
| Chicken Types | Perch Space/ bird |
| Layer | 25cm (10 inch) |
| Dual Purpose | 20cm (8 inch) |
| Meat | 15-20cm (6-8 inch) |
Conclusion
Perching is the bird’s normal behaviour in the wild. Perches in chicken housing can enhance the natural behaviour of the birds which also accounts under enriched housing of poultry. However, the arrangement, design and material of the perches is crucial to avoid any injuries proper guidance must be taken to built it. Also, letting the birds carry out this natural task is one approach to lessen stress in the laying hen which can have significant commercial implications.