A literature review was undertaken to examine welfare issues in the turkey farming sector. The major issues are diseases, poor locomotion due to high growth rate, behavioral problems caused by high stocking density, lack of environmental enrichment in the turkey house and in the free range and poor air quality in turkey sheds.
In Australia, vertically integrated companies Ingham’s and Baiada produce more than 75% of the turkeys. Other large independent growers produce an additional 1.0 million turkeys, with the remainder (100,000) coming from small operations in each state. In 2007, turkey production comprised 22,000 tonnes of meat ($56m) with exports valued at $6.24m. Turkey stock of high genetic merit is imported into Australia from the USA and UK on an infrequent basis. Over the last years, there has been an interest in developing an understanding of the major issues being faced by the Industry.
Hatching and housing
In the hatchery, there are some negative effects of long-term storage of turkey fertile eggs. Storage for more than one week increases embryonic abnormalities and chick mortality and post-hatch growth and quality of surviving birds is also affected.
There is a view that turkey welfare is improved if birds are housed on deep litter in naturally ventilated sheds with natural light and access to forage and shelter belts.
However, problems have been observed in the outdoor system with an increase in mortality usually caused by very hot or cold environmental temperatures.
Economic losses occur every year because of mortality and decreased production due to high environmental temperatures. Stocking density is an important issue in turkey welfare with high stocking density being a major animal welfare concern. It is a very sensitive subject because the whole economic balance of turkey production is very dependent on high stocking densities. Currently, there is a wide range of recommendations for stocking densities for growing turkeys. Birds reared at a density of 8 birds/m2 showed a higher incidence of hip lesions such as scabs and scratches and of foot pad dermatitis (FPD) than those reared at 6.5 or 5 birds/m2, indicating that bird welfare is compromised at the highest density. The barren environment of turkey houses has often been identified as a major cause of poor animal welfare and predisposes cannibalism. Use of straw bales in the shed and elevated platforms gives the bird the chance to explore the environment and reduce pecking.
The selection of fast growing strains of turkeys has resulted in leg and locomotory problems. The weight of breast muscles have increased relative to leg muscles and some birds find it difficult to move. Mortality rates caused by gait problems, range from 2-4%. Birds also have greater difficulty coping with heat stress, which is a major welfare problem in the turkey industry. Huge economic losses occur every year because of mortality and decreased production due to high environmental temperatures. However, intermittent lighting results in an increase in bird activity, which results in a higher feed intake and a decrease in locomotory problems.
Under commercial conditions, domestic turkeys are often aggressive towards pen mates, which leads to injuries and death. To prevent outbreaks of pecking and cannibalism in turkeys, the light intensity is usually set at 5-7 lux although 1 lux is sometimes used. At very low light intensity birds find it difficult to explore the environment and stockpersons cannot detect birds that are sick or being pecked.
Beak trimming is normally performed early in the life of commercial turkeys to decrease injuries caused by cannibalism, bullying, and feather and vent pecking. Beak trimming has been used for many years as a method to prevent cannibalism but the techniques (hot blade and infrared) are coming under increasing scrutiny. A number of European countries have banned beak trimming and the development of alternatives to beak trimming and re-trimming are now being given higher priority as critics become more vocal about invasive procedures applied to domestic animals.
Air quality in turkey sheds can also be a welfare issue. Poor air quality in turkey houses often occurs as farmers attempt to reduce heating costs by using high stocking densities and low ventilation rates. The key toxic gases in poultry houses are ammonia, carbon dioxide, carbon monoxide and hydrogen sulphide, together with dust. Carlile (1984) indicated that continuous exposure of poultry to ammonia increases their susceptibility to keratoconjunctivitis and respiratory infections.
Foot pad dermatitis (FPD) is a common condition amongst commercially grown turkey poults and is largely caused by litter quality. The skin of the footpad becomes hard and scaly, often developing horn-like pegs of abnormal keratin. The footpad can become swollen, frequently splitting. The cause of FPD is complex, but many reasons have been suggested, such as diet, bird weight and sex, litter moisture, litter type and ventilation. Litter quality is affected by factors such as stocking density, air temperature and moisture, season, consistency and amount of faeces and drinker design. Wet litter is one of the key factors affecting FPD, followed by biotin deficiency. Turkey poults reared on wet litter have an increased incidence and severity of FPD lesions but the problem is alleviated by replacing the wet litter with a dry one.
Good management is essential to maintain turkey welfare including taking action to minimize contact of turkeys with wild birds and other animals. Appropriate hygiene, proper housing, and brooding and adequate stocking density are essential when welfare of turkeys is being judged. The housing facilities and equipment used in turkey farming need to be cleaned and disinfected before restocking to prevent the carry-over of disease-causing organisms to incoming birds. Free range turkeys should not be kept on land which has become contaminated with organisms which cause or carry disease to an extent which could seriously prejudice the health of turkeys. The potential disease/pathogen risk pathways on commercial turkey farms have shown that drinking water, movement of personnel between sites/farms and contact with wild birds were the main potential pathways for pathogen transfer to domestic turkeys.
Apart from Avian Influenza, Blackhead is one of the most serious poultry diseases in turkeys; mortality can reach 70% in some flocks. Early signs of this disease include drowsiness, drooping of the head and wings, walking with an unusual gait, soiled vent feathers due to diarrhea and bright yellow faeces resulting from infection of the liver.
Pickup and transport
The pick-up of turkeys from sheds for transport to processing plant can result in welfare concerns. Catchers are often required to carry birds upside down through a shed to a truck outside especially when the containers cannot be taken inside the shed for biosecurity reasons. Birds are usually caught by one or both legs and then placed into the crate. During this procedure the heads or wings of the birds can be injured against the solid sides of the crates.
Mortality has long been a concern in relation to poultry transport. When birds are being transported they are exposed to a number of stressors including temperature extremes, sudden acceleration and braking of the vehicle, vibration, abrasion on the crates, fasting, withdrawal of water, social disruption and noise. The major threat to bird welfare during transport is increased mortality due to either heat or cold stress and muscle damage.
The welfare of turkeys can be affected during most processes in the production chain. Genetic selection, housing conditions, transport and slaughter can all be causes of poor welfare. The major issues are concerns associated with disease, poor locomotion due to high growth rate, chronic pain from beak trimming, eye abnormalities from being housed under low light intensity, behavioral problems caused by high stocking density, lack of enrichment in the turkey house and in the free range and poor air quality in turkey sheds. Depopulation of sheds and transport and slaughter can also result in poor welfare for birds. Changes in the current practices may lead to higher costs, which cannot be sustained by producers.