Integration of animal welfare into assessment of broiler chicken production systems toward sustainable development in Vietnam

Han Quang Hanh, Nguyen Thi Xuan and Vu Dinh Ton

Faculty of Animal Science, Vietnam National University of Agriculture, Trau Quy, Gia Lam, Hanoi, Vietnam
hqhanh@vnua.edu.vn

Abstract

To provide insights into the need of the integration of animal welfare into broiler chicken production systems for sustainable development, this study was carried out to assess the welfare quality of broilers in two major production systems in Hai Duong province, Northeastern Vietnam, namely indoor housing system and outdoor access system. A semi-structured survey was conducted at forty farms belong to two production systems to identify the current characteristics of chicken flocks. The assessment of welfare quality of chickens was done at two representative farms.

The results showed that the fast-growing breeds (Luong Phuong and Ross 308) in the indoor housing system were suffered from some welfare issues such as lameness, bad plumage quality, severe hock burn and footpad dermatitis, and fear of human approach. The crossbred (Ho x Luong Phuong) chickens in the outdoor access system had a better welfare quality than that of the indoor housing system. Improving the production facilities and management should be taken into account by farmers to enhance the welfare quality of animals.

Keywords: animal well-being, poultry welfare, welfare quality

Introduction

The broiler production system is a great important factor affecting levels of comfort, welfare, health and production efficiency of birds (Fouad et al 2008). The two major broiler rearing systems in Vietnam are indoor housing system and outdoor access. In general, the free-range system requires more space, however, the bird’s sanity is ensured through performing dust-bathing and other behavioral activities (Fouad et al 2008). Conversely, although indoor housing system is equivalent to the most economic use of land and labour (Awoniyi 2003), its drawbacks are vulnerable to social stress (Swain et al 2002), lack of physical space, behavioral limitations and environmental shortage (Duncan 2001).

Consumers believe that the meat of free-range chickens is healthier than that of broilers kept in a confined system (Fanatico et al 2006). Pavlovski et al (2009) also reported that less intensive management systems increase welfare levels of chickens and produce much higher quality products. Because chickens kept in free-range systems have more chance to express their natural instincts compared to confined birds (Sosnówka-Czajka et al 2007). Consequently, the interest of poultry producers and consumers towards systems and technologies that ensure access of birds to outdoor, low stocking density and natural lighting is increasing.

In Vietnam, poultry production plays a crucial role in the household economy and the production of meat. Broiler meat is ranked second of the total quantity of meat consumed every year right after pork (about 18-20% of the total amount of consumed meat). From 2002 to 2012, the total domestic consumption of meat had increased by 102% and the per capita broiler meat consumption increased from 4.26 kg to 7.60 kg (USDA 2012). The chicken meat production system has evolved significantly from an extensive production system into an industrialized intensive system during the period of accelerated industrialization and urbanization process.

The welfare of farm animals, especially broiler chickens, is a new concept to both producers and consumers in Vietnam. There are neither regulations nor legal norms or public standards currently available for the welfare of farm animals in Vietnam (Eurogroup for Animals 2013). In comparison with laying hens, there is no clear evidence for the mistreatment of broiler chickens. Scientists are only given some recommendations for relative changes rather than binary changes for welfare improvement of broiler chicken production systems, making it difficult for producers in practice (Scientific Committee on Animal Health and Animal Welfare 2000).

This study was carried out to examine current characteristics of broiler chicken production, to assess broiler welfare quality and consequently, to propose several implications for the sustainable development of the broilers indoor-housing system and outdoor access.

Materials and methods

Location of study

The study was conducted in Hai Duong province, Red River delta, Northern Vietnam as the total poultry population of the province (in the period of 2000-2016) ranked the second in the Red river delta, Northeastern Vietnam (General Statistical Office 2017).

Household Survey

The informal survey method was implemented through interviews with local officials (Provincial Department of Agriculture and Rural Development, commune veterinary staff) to investigate the general context of broiler production development and classify the common types of broiler rearing systems in the province. Moreover, statistical data on the broiler production scale and flock structure were also analyzed. A list of households and chicken farms was provided by the local staff, which was used as the basis for sample selection. The household survey was a semi-structured interview and covered characteristics of broiler rearing systems. Forty out of seventy-six broiler farms were randomly selected for the survey: twenty-five farms in outdoor access systems in Cam Hoang commune and fifteen farms in completely indoor systems in Cam Dong commune, Cam Giang district, Hai Duong province. Data was collected by a semi-structured questionnaire throughout the in-depth interview with heads of households.

Behavioral observations and welfare assessment

Two representative farms belonging two production systems (each per system) were selected for the welfare assessment of broilers. In the outdoor access system, a small flock (500 chickens) of crossbred (Ho x Luong Phuong) chicken that popularly reared by most farms was measured. In the indoor housing system, one flock (500 chickens) of Luong Phuong breed and another flock (500 chickens) of Ross 308 breed were chosen for the assessment.

Chicken behavior and health assessment were done by one person at the slaughter age (within 5 days before dispatching). For the behavioral assessment, the human-animal relationship was assessed by the avoidance distance test (for crossbred (Ho x Luong Phuong) chicken in outdoor access system) and touch test (for Luong Phuong and Ross 308 chickens in indoor housing system). These tests were conducted throughout focal scanning on a number of focal chickens (Graml et al 2008; Welfare Quality® 2009). Chickens were chosen randomly for the assessment of some health parameters (plumage cleanliness, lameness, hock burn, and footpad dermatitis) according to the Welfare Quality® Assessment Protocol for Poultry (2009). At least 100 heads of chickens were picked up randomly from 10 locations in the house to check the plumage cleanliness, hock burn and footpad dermatitis by direct observation and scoring according to the severity of the lesion (0 denoted no lesions/lameness and highest score denoted severe lesions/lameness).

Data analysis

Data were analyzed using Microsoft Excel® program and Minitab software version 16.1. Descriptive statistics contain mean, standard deviation, median, min, max and percentage.

Results

General characteristics of broiler rearing systems

The main differences between outdoor access and indoor system were breeds, production scale and raising methods (table 1). In the outdoor access system, most of the households kept slow-growing chickens, (Ho x Luong Phuong) breed, in small and medium scales (500 birds/production cycle and 6 production cycles/year). A majority of these households applied traditional VAC (garden-pond-livestock) integrated systems to maximize the utilized area of the garden for free-range chickens. The area of the barn was relatively small (50 m² per household) and the garden area was relatively large (166 m² per household). For the indoor housing system, most households raised Ross 308 breed and only several farms have recently switched to Luong Phuong breed. The average chicken flock size per household was high (4100 birds/production cycle and 8 production cycles/year).

Housing conditions are closely related to welfare quality of chickens. The outdoor access system has made crucial improvements for animal’s requirements. Chickens were not only given free access to an outdoor area during the daytime but also provided an enriched environment allowing them to express natural behaviors such as perching (32% of households), outside dust-bathing (80% of households) and garden had shading areas (100% of surveyed households). Drinkers and feeding troughs were placed outside to ensure free access of the chickens to water and feed freely.

Welfare quality parameters of broilers

Plumage cleanliness and lameness. There were differences in plumage cleanliness of three broiler breeds in two housing systems. Under outdoor access system, 67% of (Ho x Luong Phuong) chicken had completely clean plumage and none of them had dirty plumage (table 2). Because (Ho x Luong Phuong) chickens are released into the backyard, bathed in the sand and sunbathe, hence, their feathers become cleaner and smoother. Under indoor housing system, there were higher percentages of chickens with slightly, moderately dirty and dirty plumage as compared to the outdoor access (P<0.05). Large body weight and high stocking density of Ross 308 chickens make them spend most of their time lying on the bedding and resulting in a high percentage (50%) of moderately dirty plumage.

Lameness prevalence was different between the three breeds in two housing systems (P<0.05). The percentage of normal, dexterous and agile chickens in Ho x Luong Phuong was very high (93%). In contrast, there was a relatively high percentage of lameness under indoor housing system. For Luong Phuong breed, 17.6% of chickens had a definite and identifiable abnormality of walking. For Ross 308, 40.8% of broilers had a definite and identifiable abnormality of walking and 28.8% of broilers had an obvious abnormality, affects the movement ability.

Hock burn and foot pad dermatitis

There was only 4% of slow-growing chickens (Ho x Luong Phuong chickens) from outdoor access system and 2.5% Luong Phuong chickens from indoor housing system got hock burns (table 3). Prevalence of hock burns was mainly in fast-growing breeds which raising indoor (Ross 308) with 20% of very small discoloration (<20% of the hock width) and 30% of moderately sized dark discoloration (40 to 60% of hock width). Prevalence of foot pad dermatitis in chickens was low in outdoor access system compared with those in the indoor housing system.

Avoidance distance test and touch test

We found a similar avoidance distance (62.6 – 68.2 cm) on chickens in two flocks of the outdoor access system. The touched percentage of chickens in the indoor housing system after 21 tests was relatively high (70.4% for Luong Phuong and 63.2% for Ross 308) (table 4), showing a bad human-animal relationship in the indoor housing system.

Discussion

Surveyed results indicated that a high proportion of chicken farms in the outdoor access system provided birds with perches and dust baths. It has been revealed that dust-bathing reduces the level of feather lipids, thereby increasing the insulation capacity of the plumage (Anna and Linda 2005). Dust-bathing is also socially facilitated. In addition, long-term dust-bathing could improve leg condition (Sara et al 2004). The presence of a satisfactory substrate is a crucial stimulant for evoking dust-bathing, and substrates with a fine structure such as sand (which was observed in the present study) or peat are preferences of birds (Sara et al 2004, Anna and Linda 2005). Moreover, these authors supposed that if the substrate is integrated with the indoor housing with light and heat as being observed in outdoor access system in this study, dust-bathing is further stimulated. As most farms sell the live birds and the price negotiation between producers and buyers is often according to the plumage condition and leg lesion severity of chickens, it could be seen that farmers have gradually improved livestock conditions towards better meeting the needs of the animal in order to increase livestock productivity and economic efficiency.

In the indoor housing system, the indoor climate was partly regulated and hence, its stocking density was higher than that in the outdoor access system. However, high stocking density limits the chickens in exhibiting natural behaviors and they are not provided by perches or dust-bathe. Most farmers explained that perches or dust baths made the daily rearing practices (feeding and water supplying) more inconvenient. They also thought that broilers kept indoor has not performed the perching or dust bathing due to their inactivity. These issues have an impact on broiler welfare.

For birds, plumage condition plays a specific role in their life. They supplied the bird with warmth and aid in thermo-regulation. Plumage also protects the bird against environmental and social implications. Therefore, plumage condition reflects health and welfare quality of the bird. If the birds had bad health, poor nutritional status and living conditions, their plumage will easily be worn and drop off. In addition, plumage condition is an indicator reflecting litter quality. Broilers need a comfortable resting place. Thus, plumage cleanliness was used to assess welfare quality of broiler chickens. Consequently, in order to improve plumage cleanliness, it is of importance to ensure bedding quality (not too dirty and wet). At the same time, perches should be provided to reduce the time of lying on bedding.

The high prevalence of lame chickens in the indoor housing system is primarily because they are selectively fast-growing bred so that their legs cannot support their rapidly increasing body weight (Jacky et al 2005). Moreover, they are kept in overcrowded houses that can affect their health. In the outdoor access system, birds have approached to an outside area promoting foraging, feed selection and activity and thus improving walking ability of the birds. Results of this study are consistent with the conclusion of Compassion in World Farming (2013) which reported that fast-growing chickens have a higher rate of lameness than slower-growing breeds. Birds with severe walking problems are experiencing pain, become less active and have more leg disorders. In addition, genetic selection, environmental factors and the interactions between them are crucial causes of lameness in birds. Therefore, in genetic selection for fast growth, more attention should be paid to the effect of growth rates on animal welfare indicators. At once, stocking densities and outdoor access should be improved to offer the potential for higher welfare for broiler chickens.

Footpad dermatitis - the inflammation of the skin on the hocks and feet is a common problem in broiler production and is frequently more severe in fast-growing breeds (Compassion in World Farming 2013). This caused by prolonged contact between the bird’s skin and wet – dirty beddings and other factors such as health status, diet and indoor climate conditions. In severe cases, the lesions can develop into inflamed ulcers which cause pain to the birds. The results of hock burn and footpad dermatitis prevalence in our study were in line with recent surveys in EU that there were about 20% of fast-growing broilers got hock burns and 22% of them got footpad dermatitis while the prevalence of these lesions in slow-growing chickens were 1% and 7%, respectively (Welfare Quality® 2009). Broilers were found less active than other chickens to maintain their fast growth rate. Fast growing broilers spent less time walking/running, scratching/pecking beddings and perching but more time in sitting and eating/drinking as compared to slow growing birds (Bokkers and Koene 2003). Consequently, their legs weaken and are not strong enough to support their heavy weight. Therefore, housing facilities, stocking density, bedding quality, perches and other enriched factors should be improved to stimulate the activeness of broilers.

Approach and avoidance reactions of animals towards humans reflect the animal’s perception of humans (Graml et al 2008). Regular interactions between human and birds could reduce avoidance and increase approach reactions of birds. Graml et al (2008) found that an average avoidance distance on laying hens in 10 free-range flocks was 65 cm. Bassler et al (2013) established an avoidance distance of 68 cm on commercial broiler chickens. In the indoor system, broilers had long dark period and thus, greater quantities of birds staying within arm’s reach when touched (Bassler et al 2013). It was easier to touch broilers in the indoor system due to the association between longer dark periods and decreased stress responses and fear of humans (Bassler et al 2013). In contrast, chickens which are given access to an outdoor range during the daytime, they are frequently exposed to natural daylight and more active than indoor broilers. Therefore, they have better reactions to stressors and are more difficult to touch compared with indoor broilers. Graml et al (2008) suggested that close contact during husbandry procedures involving talking and feeding a small amount of grain could efficiently improve the relationship between human and animal. In addition, enriched environment such as perches should be provided to improve the human-animal interactions and get chickens used to stressors.

Conclusions

• Broilers in the outdoor access system had a good welfare quality while those in the indoor housing system had several welfare issues related to plumage cleanliness, hock burn, footpad dermatitis, walking ability, and inactive response to humans.

• Therefore, we suggest that the broiler producers should improve the production facilities and management by providing the birds with some enrichments (such as perches, dust baths) to enhance the welfare quality of chickens.

Acknowledgment

The authors gratefully acknowledge the International Foundation for Science for the financial support for this study.

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Received 3 April 2019; Accepted 11 April 2019; Published 1 May 2019

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