From the poultry producer’s point of view, ensuring high bird welfare is very important for economic reasons. A high level of welfare enables optimum growth rates, high laying rates or daily gains. Minimising the impact of negative factors, such as disease, reduces treatment costs and the use of antibiotics. This is very important for the consumer, as such meat, or eggs, will meet all quality and food safety standards.
Broilers represent the largest population of productive birds in the world. Keeping very large numbers of birds in one production facility generates serious problems for their welfare. Welfare should be assessed using measurable indicators. Thus, attention should also be paid to feed availability and area per bird. Guided by these indicators and thresholds adapted to the situation – including genetic factors (the genetic lineage of the birds) – it will be possible to maintain welfare at a high level.
18.104.22.168 Key indicators of broiler welfare:
- Mortality and morbidity. Daily, weekly and cumulative rates of mortality, falls and morbidity should be within expected ranges. Any unanticipated increase in these rates may reflect an animal welfare problem.
- Breeding and limbs. Broilers are susceptible to the development of various infectious and non-infectious musculoskeletal disorders. These disorders can lead to lameness and gait disturbances. Birds having difficulty moving and reaching food or water may be trampled by other broilers and may experience pain. Musculoskeletal problems have many causes, including genetic, nutritional, inadequate lighting, litter quality and other environmental factors. Several systems are available to assess bird movement.
- Foot sole dermatitis (FPD). Contact dermatitis affects skin surfaces that come into prolonged contact with wet bedding or other wet floor surfaces. These lesions manifest as blackened skin progressing to erosions and fibrosis on the lower surface of the foot pad, at the back of the ankle joint. If intense, they can contribute to lameness and lead to secondary infections. At the same time, inflammation of the skin may occur in the breast area. Reliable scoring systems for contact dermatitis have been developed for abattoirs.
- Feather condition. Assessment of the plumage condition of broilers provides useful welfare information. Soiling of the plumage is correlated with contact dermatitis and lameness in individual birds or may be related to housing conditions.
- Prevalence of disease, metabolic disorders and parasitic infestations. Poor health, regardless of the cause, is a threat to welfare.
- Fear. With this behaviour broilers avoid people, this behaviour is observed in flocks where the animal keepers walk quickly around the hen house while doing their work. Fear (e.g. sudden loud noises) can also lead to broilers crowding and even choking each other. The growth rates of such birds are lower.
- Spatial distribution. Changes in the spatial distribution (e.g. clumping) of birds may indicate thermal discomfort or the presence of areas of wet litter or an uneven supply of light, food or water.
- Puffing and wing spreading. Excessive panting and wing spreading indicates heat stress or poor air quality, such as high ammonia levels.
- Feeding, drinking and foraging. Reduced feeding or drinking behaviour may indicate organisational errors, including inadequate feeding or watering space or place, poor water quality or contaminated feed. Feeding and drinking behaviour is often reduced when broilers are sick. Feed intake may also be reduced during periods of heat stress and increased during cold stress. Foraging is the activity of searching for food, usually by walking and pecking or scratching the bedding substrate. Decreased foraging activity may suggest problems with litter quality or the presence of conditions that restrict bird movement.
- Feather pecking and cannibalism. Feather pecking can cause significant feather loss and can lead to cannibalism. abnormal behaviour has multifactorial causes.
- Water and feed consumption. Monitoring daily water consumption is a useful tool for indicating disease and other maintenance conditions, taking into account ambient temperature, relative humidity, feed consumption and other related factors. Problems with water supply can cause wetting of bedding, diarrhoea, dermatitis or dehydration of birds. Changes in feed intake may indicate inadequate feed quality, the presence of disease or other welfare problems.
- Productivity. Growth rate – is an indicator that determines the average daily weight gain per broiler in a flock. Similarly, feed conversion rate is an important indicator.
- Injury rate. Injury rates can indicate welfare problems in the flock. Injuries can be caused by other broilers (scratches, feather loss or injuries from feather pecking and cannibalism), caused by environmental conditions (e.g. contact dermatitis) or by human intervention such as pawing. The most common pawing injuries are bruises, dislocated hips and damaged wings.
- Eye condition. Conjunctivitis can indicate the presence of irritants such as dust and ammonia in the air. High levels of ammonia can also cause corneal burns and eventually blindness.
- Vocalisation. Can indicate emotional states, both positive and negative. Interpretation of flock vocalisation is possible by experienced staff.
The health status of poultry is indicative of the level of welfare, the level of which affects their health. Reduced levels of animal welfare promote disease and all kinds of technopathies, i.e. diseases and injuries associated with poor housing conditions. Among the most commonly enumerated technopathies in poultry are disorders of the limbs. These conditions are described in hens that have been kept in systems that limit the surface area for activity. Stereotypes, or unnatural animal behaviour, can also occur. Avian stereotypies include pterophagia, or the pecking out of feathers of other birds, and cannibalism. Hens have a natural need to peck and cluck, perch, ruffle their feathers, take sand baths and exercise. Depriving birds of the opportunity to manifest their natural needs is a stressor. This can lead to the onset of disorders, which become a major problem for the animals, as well as for breeders, and can cause losses.
The most important problems associated with poor maintenance and deterioration of welfare are:
Feather pecking (pterophagia). The causes of this type of aggressive behaviour are dietary errors, especially vitamin K deficiency. There are also genetic causes. In addition, the severity of pterophagia symptoms can be influenced by external parasites and skin diseases. There are several categories of this phenomenon in laying hen flocks: gentle pecking, increased pecking, pecking at the steak area. It can develop into cannibalism. The most effective prevention of the occurrence of this stereotypy is to ensure optimal feeding and environmental conditions and enrichment of the environment.
Cannibalism. Cases of cannibalism occur in all types of poultry husbandry, but more frequently in large free-range flocks or aviaries. Environmental factors contributing to cannibalism include: rearing birds at excessive stocking densities with too little humidity and too much light. Inappropriate diet can also have an impact. Deficiencies in protein, especially of animal origin, B vitamins, calcium, fibre and minerals, can also exacerbate the symptoms of cannibalism. A high maize content in the feed and pelleted feed, which is taken up more quickly than loose feed, are also predisposing factors. Other inappropriate technological solutions are also mentioned among the relevant factors. Too few nests or the inconvenient positioning of feeders and drinkers for the birds can be a cause of aggressive behaviour. Irregular feeding and watering of birds also adversely affects their behaviour. Preventive elements include: appropriate diet, removal of individuals with visible bleeding wounds, selection of genetic lines for gentleness and technological solutions (e.g. quality and number of nests, perches etc.).
Poultry footpad dermatitis (FPD) is a type of contact dermatitis, mainly of the soles of the feet and the skin around the ankle joint. It occurs mainly in broilers. It is a typical technopathy that develops in 2 stages:
Stage I – irritation of the skin surface and formation of inflammation. The main visible symptom is redness, followed by shallow erosions and the formation of so-called corns.
Stage II – begins when the skin barrier is broken, bacteria cause purulent inflammation. Intense ulcerations and abscesses appear.
The incidence of footpad inflammation is one of the determinants of poultry welfare. In practical terms, a number of scoring measures have been developed to indicate poultry housing conditions and reflect welfare levels. The accepted scale for assessing inflammatory lesions on the sole skin is:
- 0 – no change,
- 1 – superficial lesions, discolouration no more than 0.5 cm in diameter,
- 2 – deep lesions with scab and ulceration, hyperpigmentation of 0.5 cm or more in diameter.
The health of chicken feet is influenced by various factors, such as genetic predisposition, environmental factors and the quality of nutrition and bedding. The incidence of FPD decreases in warm, dry seasons and increases in colder months. Particular attention is paid to the type and quality of bedding material, especially its moisture content. The type and composition of the feed given are also important. Nutritional factors indirectly influence litter moisture (consistency of droppings). The high protein requirements of broilers necessitate the use of soybean meal in the diet, which contains high amounts of potassium, which has an adverse effect on faecal consistency. Also, the high mineral content of the feed can lead to an increase in water intake leading to soggy litter. Similarly, a diet high in protein has a negative effect. Excess body nitrogen from the feed has to be excreted, which contributes to increased water intake and a loosening of faecal consistency and litter dampness. In practice, therapeutic measures are usually delayed, so it is extremely important to avoid triggers for the phenomenon described.
Despite the clear economic benefits of keeping laying hens in cages, their welfare is significantly impaired as they cannot fully fulfil their physiological and behavioural needs. The restriction of freedom of movement observed in cage batteries is a major cause of limb weakness and disease. Caged hens have been found to have a higher incidence of foot keratosis, multiple foot fractures, uncontrolled claw overgrowth, fractures or dislocations of the limbs. Cage fatigue syndrome occurs in caged hens, which are often in good condition and laying hens, who are observed to suddenly roll over onto their backs with signs of osteoporosis, often accompanied by paralysis.
In 2012, due to Directive 1999/74/EC defining new standards for poultry housing, farmers were forced to introduce so-called ‘enriched cages’ – the cage area was increased, perches, sheltered nests and a claw rubbing surface and litter for burrowing were installed.
Across Europe, there are intensive efforts to reduce caged egg production in favour of alternative systems (barn, free-range, organic). Currently, an increasing number of countries in the EU are deciding to ban caged laying hens, such bans have already been adopted in Germany, the Czech Republic, Switzerland and will apply in the rest of the EU from 2025 or 2027. The alternative, of course, is free range (small-scale, large-scale or organic).