Furnished cages and free-run systems are familiar with artificial housing environments for poultry. The two systems differ in the way they cater to regular feeding/foraging, nesting, perching, and dust bathing, which are essential for the welfare of poultry. The Peach Farmhouses 20,000 laying hens in cages (40 birds per cage) while the Olive Farm is a free run system with 10,000 chickens in a divided hoop barn (5,000 hens in each half). In the context of animal welfare, both systems meet the behavioral needs of the birds to varying degrees.
Comfort feeding or foraging is a natural behavior of all birds. In the Peach Farm, the chain feeders are placed at a lower position than the average height of the hens. One bird can be seen straining its neck to reach the feeds, a scenario that has the potential of causing injury and abnormal feather pecking. In their study, Weeks and Nicol (2006) found that the absence of suitable feeders and foraging litter in conventional battery cages increases the risk of abnormal feather pecking.
Ideally, hens spend half of their time feeding and foraging. However, in the Peach Farm the time spent feeding at the feeder is less than 50% of the 16 h light period. In contrast, feeding and foraging take over 50% of the 16.3 h light period of the Olive hens. Therefore, the raised feeders, nibble drinkers, and forage litter at the Olive Farm promote comfort feeding of the chickens than the low-level Peach feeders. Additionally, the abnormal feather pecking caused by the low-level feeders may account for the significantly higher mortality at Peach Farm (2.4%) than at the Olive Farm (0.8%).
Perching and roosting is another essential behavioral need for hens. In the Peach Farm, the floor on the cages consists of wire and steel bars, which may hinder comfortable perching. In addition, the perches provided are more congested (12.4cm per hen) than those in Olive Farm (15cm per hen). Thus, there is a likelihood of pushing and aggression in the Peach Farm. Scientific literature shows that if the perch space is insufficient, birds are likely to display frustration because the intrinsic urge to perch or nest is thwarted by overcrowding (Knierim, 2006). Furthermore, abnormal feather pecking and aggression often arise in a crowded perching/roosting space.
From the slides, the laying hens in the Peach Farm become flighty and huddle in a corner when a person approaches. In contrast, the Olive hens are less freakish and do not fear people probably because sufficient perching space reduces their anxiety and restlessness (Donaldson and O’Connell, 2012). Therefore, if the perch space is sufficient, as in the Olive Farm, the hens are less likely to be flighty and fearful of people.
The lack of substratum litter in cages is repressive to the hens’ urge to dust-bathe. Experimental evidence shows that the availability of a dusty substratum stimulates the urge to dust-bathe, which is a gratifying activity for birds (Olsson and Keeling, 2005). In contrast, the littered floor in the Olive Farm is expansive, giving Olive hens a larger substratum to dust-bathe than the Peach hens (45cm by 45cm per 40 hens). Additionally, the small cage space may limit the hens’ ability to move around, which could explain the high risk of injury due to cage trauma recorded at the Peach Farm. On the other hand, the spacious Olive barn stimulates the urge to fly, which increases the risk of injury due to flying collisions. However, the large hoop barns may give the hens enough room to engage in comfort activities such as stretching and wing flapping.
Comfort behavior is restricted in a cage environment. Valkonen, Valaja, and Venalainen (2005) explain that activities such as preening and flapping of wings maintain the feathers in a healthy state. The spacing in the Peach Farm cages (660cm2 per hen) may be insufficient for hens to do simple movements. Furthermore, the limited floor space coupled with the high frequency of abnormal feather pecking may account for the high average feather score (2.9) of the Peach hens. From the pictures in the slides, it is clear that the back feathers of the Peach hens are diminishing while those of the Olive hens are thick and healthy probably because they have enough space to engage in comfort activities. This observation shows that the free-range system offers a more comfortable environment than the cage system.
A confined environment also limits the birds’ ability to exercise, which is crucial in improving bone structure and strength. Yue and Duncan (2003) found that the limited space in cages impedes free movement that essentially strengthens the muscles and bones via the dynamic loading process. In this study, up to 24% of the caged birds culled at 72 weeks had fractured bones. This problem is also observed in the Peach Farm where 18.1% and 31% of the surveyed poultry suffered from hyperkeratosis and twisted/broken keel bones. In light of this finding, it is fair to conclude that hens require more space than the one provided in cages. However, hens temporarily prefer smaller spaces when nesting (Fraser and Duncan, 2008). In this respect, the Peach Farm’s 60 by 55cm may be more preferable to the large nesting area of 110cm2 per hen in the Olive Farm.
Exploratory behavior is common among birds. Birds tend to be inquisitive of their surroundings, a trait that helps them identify a suitable site to perch/roost or nest. Research shows that environments that deprive hens of the opportunity to explore their surroundings affect their psychological well-being because exploratory behavior lies “at the core of avian physical existence” (EFSA, 2005, p. 33). In the Olive Farm, the hens spend most of their time foraging for feeds from the litter, which is an environmental challenge that quells their primal instinct to search for food. In contrast, the chickens at the Peach Farm obtain their nutrition from the chain feeders. Knierim (2006) explains that hens continue to explore for food or nesting sites even when such resources are provided. Thus, the cage environment at the Peach Farm may suppress the natural exploratory behavior of the hens, which may affect their psychological well-being.
On the other hand, the free-range system at the Olive Farm is enriched with various stimuli, including litter and dust-baths, which appeal to the natural tendency of chickens to explore and manipulate their environment. The hens have the opportunity to investigate the litter for feeds, perch on the superstructure of the hoop barn, and choose a nesting site from a range of options. The variable environment matches the intrinsic desire to explore and interact with different objects. The engaging environment in free-range systems reduces the frequency of feather pecking and improves the hens’ quality of life (Fraser and Duncan, 2008). In the slides, the Peach Farm hens engage more in feather pecking than the Olive Farm chickens probably due to the lack of exciting stimuli in the cages.
In conclusion, evidently, the free-range system in the Olive Farm is better for the welfare of the laying hens than the cage environment of the Peach Farm. Overall, the Olive Farm appeals to the psychological and behavioral needs of laying hens, such as comfort feeding, perching, dust-bathes, exploration, and exercising, more than the Peach Farm does.
References
Donaldson, C.J., and O’Connell, N.E., 2012. The influence of access to aerial perches on fearfulness, social behaviour and production parameters in free-range laying hens.. Applied Animal Behaviour Science, 142: 51-60.
EFSA, 2005. Scientific report on the welfare aspects of various systems for keeping laying hens. European Food Safety Authority, London, p. 33.
Fraser, D. and Duncan, I.J., 2008. Pleasures, pains, and animal welfare: Toward a natural history of affect. Animal Welfare, 7: 383-396.
Knierim, U., 2006. Animal welfare aspects of outdoor runs for laying hens: a review. Wageninhen Journal of Life Sciences, 54: 133-145.
Olsson, I.A. and Keeling, L.J., 2005. Why in earth? Dustbathing behavior in jungle and domestic fowl reviewed from a Tinbergian and animal welfare perspective. Applied Animal Behavior Science, 93: 259-282.
Weeks, C.A. and Nicol, C.J., 2006. Behavioral needs, priorities, and preferences of laying hens. World’s Poultry Science, 62: 296-307.
Yue, S. and Duncan, I.J., 2003. Frustrated nesting behavior: relation to extra-cuticular shell calcium and bone strength in White Leghorn hens. British Poultry Science, 44: 175-181.
Valkonen, E., Valaja, J. and Venalainen, E., 2005. The effects of dietary energy and perch design on the performance and condition of laying hens kept in furnished cages. Institute of Genetics and Animal Breeding, Lublin, Poland. pp. 91-103.