HANDLING AND TRANSPORTATION OF BROILERS WELFARE, STRESS, FEAR AND MEAT QUALITY

ISRAEL JOURNAL OF

VETERINARY MEDICINE

Review: HANDLING AND TRANSPORTATION OF BROILERS WELFARE, STRESS, FEAR AND MEAT QUALITY Part IV: Handling of Broilers

K. Elrom dr-elrom@newmail.net The Technion - Israel Institute of Technology, Faculty of Food Eng. & Biotechnology 32000 Haifa, Israel. AbstractHandling (syn. catching, depopulation, harvesting) of broilers prior to transportation to the slaughterhouse causes a severe stress to the birds if not the severest in their short life. In Israel depopulation of birds is done mainly by catching crews. Many works in the professional literature, indicate that the use of a mechanic combine, which was developed for this purpose is preferable to manual handling on economic and welfare considerations. The birds are fasted for 6-12 hours before catching and water is removed one hour before catching. The fast, the presence and smell of man, the machinery, the accompanied noise and the social mixing are all potent offensive factors of the bird's welfare, which grow almost without the sight and touch of man. It seems that the mechanical combine decreases the DOA values, improves the welfare of the birds and decreases bruising, bone fractures and skin torsion.

General aspects of handling and transportation of broilers There are severe welfare problems associated with pre-handling, handling and transport of broiler chickens as assessed by many research workers. Handling and transportation may adversely affect mortality and product quality. Transit birds are exposed to a wide variety of potential stressors such as the withdrawal of food and water, fractures, bruises, pain, stocking density, social disruption, transport micro-environment, motion, acceleration, vibration, noise and restriction of behavior. These factors, individually or in combination, attribute to the evaluative parameters as: dead on arrivals (D.O.A), physical injury, carcass characteristics, physiological stress responses and fear responses. Increased automation of handling procedures may be one way to reduce physical damage and stress but there is evidence that movement is also a potent stressor (1, 2). Possible outcome of welfare problems associated with catching, transportation and unloading: (3)

v Death Metabolic exhaustion Bruising Dehydration Broken bones Emotional stress Torn skin Thermal stress

Time of handling and transportation. At harvesting, when crowding is most severe, dim lights or near-darkness are used on many farms to reduce stress and fighting. Harvesting and transportation are usually done at night or early morning hours when roads are free of traffic jams and animals can be transported to the slaughterhouse without delay. Moreover, the weather at this time of the day, especially the temperature, is usually more suitable. Catching in the dark has been shown to have beneficial effect on broilers and to a large extent this is already a common commercial practice (4). Nicol and Scot (2) add that it is also to ensure a constant supply of birds to the slaughterhouse which usually starts to work very early. Buyse et al.,(5) reported that using intermittent lighting (IL) increased the damage during handling but improved the welfare of broilers. They add that it also reduced physiological stress and improved eye condition during their life. IL may be improved by modifying light management before the catching operation to improve the welfare. Pre-handling stressors Fasting and weight loss Fasting before and during transportation is a major stressor. Food is removed approximately 6-12 h, and water approximately 1 h, prior to catching. This is to reduce carcass contamination in the event of punctured intestines during evisceration at the processing plant (2,6). The overall weight loss is a commercial problem, and depends both on the duration of fasting and the climate during transportation. After 6 h of fasting the intestinal content is minimal and liver glycogen is negligible (7). It is also suggested that fasting may also improve the impact of thermal stress because heat is produced by metabolism of food. Generally, weight loss occurs after 4-6 h of fasting at a rate of 0.2-0.5% h-1 as birds begin to metabolize body tissues (7). Dehydration in hot weather is a major welfare problem if water is withdrawn too early prior to catching (2).

Handling (syn.: Catching; harvesting; depopulation) At night when the flock is ready for the slaughterhouse, the birds are crowded toward one end of the building. Then, when birds are drowsy, the crews of catchers or the mechanic harvester begin work, catch and load them in crates. Research has shown that handling alone significantly raised plasma CS (corticosterone) concentration in young chicks. Duncan (8) found similar evidence of elevated heart rates and CS concentrations in older birds in response to manual catching and restraint. The stressor effects of such contact were so pronounced that inversion of the birds, or deliberate rough treatment, had no additional effect. These results are supported by an experiment which compared the heart rate of birds caught and loaded by hand with those caught by a harvester (9). Heart rates in both groups rose to similar levels during catching but dropped more quickly when using the harvester. Effects of catching and crating procedures have been shown to be stressful (2).

Reliance on human labor seems old fashioned, and the broiler industry is trying to raise birds in cages similar to those used by egg producers. Birds could then be reared and shipped to the slaughterhouse in the cages they were reared. There are problems yet unsolved, which prevent the farmer to use this growing method in a wide scale, such as developing breast blisters, bruises and foot and leg injuries (10). Mason and Singer (11) in 1980 reported in their fascinating book, Animal Factories that they were undaunted that the breeding companies were trying to perfect a strain that can withstand the cages : Once they succeed, the broiler industry will switch to these birds and retool for more thoroughly mechanized production. They added that poultry growing units will become larger and cage production of broilers will gradually take over. The new factories will move the birds to larger equipment in which a push-button control system will move the belts supporting the cages. The housing units will be on a flow basis: chicks will enter at one end and the finished live broiler will come out at the other. Nicol and Scot (2) have also mentioned that broilers can be reared and transported in the same cages, although hygienic implications of re-using equipment from the processing plant would have to be considered. Such systems would reduce the trauma of catching and loading, other welfare problem may arise such as bruising and musculo-skeletal lesions that may arise. Such systems will eliminate the labor of catchers, moreover, cages can be stacked so farmers will be able to house three or four times more birds in the same space. Another way to eliminate the labor of catchers was to use the mechanical harvester.

The presence of man and machinery Manual catching groups do most of the harvesting today. Another new method of harvesting introduced recently is the combine or mechanic harvester. The presence of man and machinery in the chicken house at the time of harvesting may cause panic and unfamiliar events and stimuli are major potent stressors for the birds. Broilers are reared in a closed environment and as such are exposed to very few, if any, external stimuli. The presence of unfamiliar people, the catching team, in the house, their odor, touch, sight movement, size, voice are all striking and stressing stimuli (12). It is known that birds see men as predators rather than naive creatures (8, 12). Presence of man and machinery during harvesting can elicit various stress reactions as inhibition, withdrawal, panic and violent escape. At this stage these reactions are associated with injury, since birds are crowded in one area of the house during harvesting. It is indicated that such responses may be decreased by customizing the birds to such stimuli early in life (12). At this stage increased levels of CS, increased heart rate - tachycardia, increased heterophil:lymphocyte ratio and increased respiration - tachypnea are seen (2, 4). Catching crew The broiler bird is customarily caught by the leg, inverted and carried by a catcher with 3-4 birds in each hand to be placed in crates, which are located inside the broiler house or outside on the transport. It is recommended to carry the bird with both legs, but this recommendation is, unfortunately, widely disregarded (13). In layers, it is also recommended that the breast of the bird will be supported during removal of batteries to prevent contact with the feed trough (14). Catchers must wear a protective mask because of the dusty atmosphere during harvesting (6). Many authors mentioned differences in physical damages and D.O.A. percentage of birds due to different catching and loading crews. Knowles and Broom (4) mention one research in which they compared normal handling of spent hens with gentle handling. The hens were carried for 90 s either in inverted manner or gently in an upright position. Blood sample of both groups showed that birds handled gently had consistently lower CS level in blood than those carried inverted. Knowles and Broom (4) cited similar research done by Duncan and Kite (15) who instead of layers, used broilers. Their results showed no differences between broilers, carried inverted, and broilers carried upright, in plasma CS, heterophil:lymphocyte ratio, duration of TI and latencies to resume feeding, drinking and social contact as welfare indices. D.O.As birds are not allowed for human consumption so the losses may be high when catchers are not careful and gentle as far as they can. A catching team may be expected to load between 1000 1500 broilers per man / h, but if catching usually takes 5 h period, it is difficult to maintain the same working rate (14). Mechanical harvesting / combine A number of mechanical catching harvesting / catching devices have been developed for broilers, which seems to improve the welfare of the birds in some respects (4,6,12). It is shown that TI (Tonic Immobility) and heart rates indicate a higher prevalence of stress in manual catching (4,9,13). Nicol and Scot, (2) described a model in which approximately 6000 birds are caught per hour. In Israel catching crews does most of the harvesting and the experience with the combine did not fulfil the expectation of farmers. Apparently the farmers are more conservative in Israel then in the U.K. and in the U.S.A., where more experience has been acquired (10). One of few mechanical harvesters was adopted in the U.K. This system consists of a self-propelled harvester, which is driven into the broiler house. The harvester has a central retractable boom and sweeper arms fitted with rotating, foam rubber paddles or rotating rubber fingers, which move the birds onto an inclined conveyor. Some harvesters are based on a pneumatic system, which sucks the bird off the floor (14). Birds are then transferred into a dump or unrestrained draw module located behind the harvester. The problem in Britain is that broiler-growing house restricts the movement of the harvester owing to some obstacles in the house and this is why these systems have not been adopted more widely. Table 1: Mechanical versus hand catching of broilers United Kingdom data, age of broilers: 50 days. Damage Harvester (%) Hand (%)

*AVG Farm 1 Farm 2 Farm 3

D.O.A 0.24 0.4 0.29 0.37 0.56

Broken legs and wings 2.82 8.4 7.68 7.25 10.04

Bruises 1.34 10.21 9.6 11.85 9.18

Overseas data (Outside of U.K) Damage Harvester (%) Hand (%) Improvement (%)

D.O.A 0.24 0.32 25

Broken legs 0.35 1.52 77

Broken wings 2.45 3.53 30

Bruises 1.34 8.43 84

Modified from: Gracy and Collins (16)* AVG = Average of farms 1,2 and 3.

Disturbing social factors Social disruption is known to be an important stressful mental factor (10,12,17), though it has been found that there were no differences in stress reactions between crated group of familiar broilers to a crated mixed group of unfamiliar broilers (TI, plasma CS and heart rate, were all increased due to the crating and not due to different social group). Williams et al., found that mixing with unfamiliar companions elicited stress responses in birds in familiar surroundings (18). Most of the work in this field indicates a severe stress reaction to social mixing. Taking into account that the bird was descended from the jungle fowl, that lives in small groups, knowing all members in the flock, it may be assumed that there is a great logic in the stress reaction in a social mixing condition. It seems that the intensive rearing systems did good for man but did wrong for the psych of the animal.

Dropping the broilers to the cratesA positive correlation have been found between the distance of dropping (max. 40 cm) with the level of CS, while high distance dropped broilers have higher levels of CS. Broilers, which are dropped from longer distances, flapped their wings and so are more vulnerable to damage during crating. Stocking density

Density of crated broilers has a major role in the ability of the bird to cope with environmental changes as homeotherm animal. The density must be determined according the crates manufacture directions (code of practice) and according to the weather conditions. The stocking density for each decision is usually determined by total live bird weight and depends on both sex and age of the birds to be transported. An empirical decision is also made in hot and humid weather to reduce the number of birds per crate. This reduction is compromised between reduced number of bird per crate to prevent suffocation / heat stroke and the need to put sufficient birds in one crate in order to prevent lateral movement which may result in physical injury. Other precautions must be adopted in other adverse weather conditions such as rain or low temperature by fitting a wind deflector above the vehicle, to protect the front leading module. The birds located on the sides can also be protected by lowering side screens before departure from the growing farm (6). Bayliss and Hinton (6) mentioned the code of practice for determining the density of broilers in a crate: Table 2 - Code of practice for crate stocking density (bird/crate) according to prevailing weather conditions. Live weight (Kg) Normal temperatures Abnormal hot conditions

1.86 30 27

1.90-2.05 27 24

2.08-2.27 24 21

2.31 21 18

This code of practice also determines that the modules must be protected with sheets in the event of cold weather (around 0_ C and below) or when it is cold and there is heavy rainfall and when the journey exceeds kilometers.

Crating systems

According to British legislation concerning transportation of poultry, crates (containers) must be so designed and used that will (14): 1. Protect the bird from injury or unnecessary suffering. 2. Provide adequate ventilation. 3. Are easy to clean. 4. Are escape proof. 5. Permit inspection of the birds. 6. Have no sharp edges or protrusions. 7. Are labeled or marked with the upright position, and indicate that they contain live poultry. 8. Constructed to prevent any protrusion of heads, legs or wings. 9. Maintained in good state of repair. Several crating systems are mentioned in the literature; loose crates (old crating system), fixed crates (birds are carried manually to the fixed crates on the vehicle) and modules, with metal frame that contain 4-16 crates, the frame is unloaded in the broiler house and then transported within one frame to the truck with a fork lift truck (6,14).

References : 1) Mitchell, M.A. and Kettlewell, P.J.: Road transportation of broiler chickens: induction of physiologic stress. Worlds Poultry Science Journal 50: 57-59, 1994.

2) Nicol, C.J. and Scot, G.B.: (). Pre-slaughter handling and transport of broiler chickens. Appl. Anim. Behav. Sci. 28: 57-73, 1990 .

3) Bremner, A. and Johnston, M.: Poultry Meat Hygiene and Inspection. London: W.B Sounders Co. Ltd. 1996.

4) Knowles, T.G. and Broom, D.M.: The handling and transport of broilers and spent hens. Appl. Anim. Behav. Sci., 28: 75-91, 1990.

5) Buyse, J., Simons, P.C.M., Boshouwers, F.M.G. and Decuypere, E.: Effect of Intermittent lighting, light intensity and source on the performance and welfare of broilers. Worlds Poult. Sci. J. 52: 83-86, 1996.

6) Bayliss, P.A. and Hinton, M. H.: Transportation of broilers with special reference to mortality rates. Appl. Anim. Behav. Sci. 28: 93-118, 1990.

7) Veerkamp, C.H.: Good handling gives better yield. Misset Int. poult. 2: 30-33, 1986.

8) Duncan, I.J.H.: The assessment of welfare during handling and transport of broilers. In: Faure, J.M. and Mills, A.D. (Eds.): Proceedings of the 3rd European Symposium on Poultry Welfare. Worlds Poult. Sci. Assoc., French Branch, pp. 93-107, 1989.

9) Duncan, I.J.H., Slee, G., Kettlewel, P.J., Berry, P. and Carlisle, A.J.: A comparison of the stressfulness of harvesting broilers chickens by machine and by hand. Br. Poult. Sci., 27: 109-114, 1986.

10) Elrom, K.: Stress in Broilers due to pre-slaughter handling and transportation. Submited as thesis for D.V.M. degree at the University of Veterinary Medicine in Kosice, The Slovak Republic. 1999.

11) Mason, J. and Singer, P.: Animal Factories. New York, Crown Publishers Inc. 1980.

12) Jones R. B.: Fear and adaptability in poultry: insights, implications and imperatives. Worlds Poult. Sci. J., 52: 131-173, 1996.