The ability to perform natural behaviour is also a major concern of welfare as in some regards, it directly affects the affective state of the animal. Due to restrictions of space and limitations of equipment/substrates, hens are unable to carry out a wide range of natural behaviours (Bulmer and Gill, 2008) such as:

• Scratching
• Preening
• Wing flapping/dust bathing
• Body shaking
• Feather rising
• Nesting

Source: Tilly’s Nest

Source: Treats for Chicken

Cooper and Albentosa (2003) suggest that ground scratching, preening, and wing flapping are valued activities that are impaired by the high stocking densities in battery cages which make it physically impossible for birds to exhibit these behaviours due to lack of space. Additional comfort activities include body shaking and feather rising which are also not permitted by space (Nicol, 1987; Keeling, 1994). In a barren battery cage, laying hens are not able to demonstrate their natural behaviour of laying in a nest. Appleby et al. (1993) found in their study that almost all eggs (95 to 100%) were laid in nest boxes when provided.

The natural living requirements of a chicken include:

• Omnivorous diet
• Fresh water
• Secure shelter
• Light exposure
• A flock

Source: Home Ecology

Hens need an omnivorous diet, known as ‘laying feed’ which they like to search for by scratching at soil. In addition, fresh water is required at all times. Further, as chickens are prey animals, they require secure shelter from predators. This shelter needs light exposure as hens lay based on daylight. Chickens should be housed in flocks as they are gregarious creatures. Specifically, hens take a communal approach to the incubation of eggs and raising their young.

However, even when natural living requirements are met, oftentimes the affective states of the animals are the next concern. This includes the lack of negative states like pain, distress, and suffering. In addition to that, many animal advocates believe that the animals’ emotions and feelings are just as important to consider when thinking of welfare (Fraser, 2008). However, it is difficult to identify and quantify certain affective states in animals as certain states cannot be observed directly. When there is no specific behaviour that accompanies an affective state, scientists may study changes in physiology as indirect evidence to prove certain states such as stress. Bulmer and Gill (2008) determined stress levels by measuring corticosterone concentrations in the eggs laid by hens housed in different farming systems. They found indications of chronic stress in battery hens. Further research shows hens in confinement experience severe frustration. However, it is also suggested that birds in battery cages are less likely to experience fear since they are housed in a stable social group with relatively few members. Regardless, around time of egg-laying, hens depict behaviours that may indicate pacing and increased aggression.

Existing biological knowledge regarding welfare concerns incurred by laying hens housed in battery cages can be categorized under three main types:

1. Natural living requirements
2. Affective states
3. Ability to exhibit natural behaviour.

Natural living requirements include basic health and functioning. This means that animals should be provided with adequate nutrients and shelter and protected from injury and disease. Ethical concerns regarding the affective states of laying hens recommend that animals should be free of negative states like pain, fear, discomfort and distress. Further, some advocates would extend this view beyond just the lack of negative states and suggest that animals should also be capable of experiencing normal pleasures and comforts. Lastly, the ability to perform important types and normal patterns of natural behaviour they are highly motivated to exhibit recommends that captive animals should be housed in an environment that is well suited to their species.

The natural living requirements of a chicken include an omnivorous diet, known as ‘laying feed’ which they like to search for by scratching at soil. In addition, fresh water is required at all times. Further, as chickens are prey animals, they require secure shelter from predators. This shelter needs light exposure as hens lay based on daylight. Chickens should be housed in flocks as they are gregarious creatures. Specifically, hens take a communal approach to the incubation of eggs and raising their young.

Despite the overwhelming prevalence of use through the globe, battery cages have been heavily criticized by animal welfare organizations and scientists (Taylor and Hurnik, 1996). Some even refer to the use of battery cages as ‘the cruelest’ of all factory farming practices (Stevenson, 2004).

Source: Sonin, J. (Photographer). (2012, January 29). Eye to eye [digital image]. Retrieved from: https://flic.kr/p/bkGdLM