Poultry welfare in different production systems

Poultry welfare is known to be influenced by housing system and management (Elson, 2010) but some aspects of it can be positive and others negative even within the same system. For example, as shown by Elson (2008), extensive free-range pasture based systems allow poultry freedom to express a wider behavioural repertoire (positive) than intensive indoor ones but expose them to greater risks of predation, climatic extremes, endoparasitic infestation and infections carried by wild birds (negative). There are also major differences in welfare between systems; hens are most confined, but also safest, in cages and have greater freedom but are at more risk of problems causing higher morbidity and mortality on free-range (Elson and Croxall, 2006).    

A range of poultry housing systems for broilers was described by Elson (1993) and for laying hens (Elson, 2003). Each of these systems was considered in relation to poultry behaviour, management and welfare by Appleby et al., (1992). An important point made by Elson (2003) is that excellence in both system design and appropriate management are essential to achieve high standards of welfare and production.

Researchers have developed welfare indicators in order to study poultry welfare within and between the different systems available (broilers: Berg, 2004 and Manning et al., 2007; laying hens: Nicol et al., 2009.). Whilst several such indicators should be used when assessing poultry welfare in different systems, some have a major influence and also are easier to measure than others especially in large scale applied studies carried out on commercial poultry farms. In this paper therefore, a few major welfare indicators that are routinely recorded on poultry farms and processing stations have been selected to assess poultry welfare within and across systems in widespread use. The main indicator used for broilers and turkeys is the prevalence and severity of contact dermatitis and, for laying hens, cumulative mortality as the flock ages.

Poultry housed on littered floor systems are at risk of developing contact dermatitis, especially if the litter quality is poor i.e. wet and/or overloaded with faeces (Berg, 2004).  This condition may present as foot pad dermatitis (FPD), hock burn or breast burn; it is seen most often in heavy broilers or turkeys and less so in laying hens, probably because most of the latter are lighter and more usually kept off litter in cages. The condition is probably painful, as a result of tissue trauma - the degree of which will vary with lesion severity (Schmidt and Luders, 1976); these lesions are frequently in contact with surfaces that increase the problem & stimulate the pain e.g. hard, capped litter.

Consumers are generally unaware of this serious welfare problem, because the legs and feet are removed at the hock from many broilers and turkeys during processing and the lesions are therefore not generally found on the finished product displayed in retail outlets. However, inspection of table poultry on processing lines reveals the prevalence and severity of the damage; it is an important welfare indicator.

Broiler production has been managed almost entirely within controlled environment housing for many years. However, niche markets were developed for slower growing free range and organically grown chickens a few years ago and production in such systems has subsequently increased. Some consumers are prepared to pay substantial premiums for these products, which are generally perceived to be produced in welfare friendly ways. However contact dermatitis has been found with much greater prevalence and severity in conventional and organic free-range chickens than in intensive systems. 

This was revealed in a large scale study by Pagazaurtundua and Warriss (2006) involving 3.93 million birds in 359 flocks on 91 farms. They found that the mean prevalence of FPD in standard intensive broiler systems was 14.8%. However, free range and organic flocks that had access to the outside showed significantly higher prevalence of FPD than those kept entirely indoors. The prevalence of FPD was higher (32.8%) in free range birds and highest (98.1%) in organically reared ones; its severity was in the same order – see table 1 below:

EU Council Directive 2007/43/EC (2007) attempted to address this issue by requiring that “all chickens shall have permanent access to litter which is dry and friable on the surface” [Annex 1.3] and that “official veterinarians shall … identify possible indications of poor welfare such as abnormal levels of contact dermatitis. … These should be communicated to the owner and the competent authority …. who shall take appropriate actions” [Annex 3.2-3]. However this has not proved straightforward (Cassidy, 2013) and in any case the Directive does not apply to broilers kept on free-range [Art. 1.1. (d)]. It should be noted that this was the first EU Council Directive to include animal welfare indicators.

Although the causal factors of FPD, including litter type and quality, drinker type, house temperature and humidity, feed composition, bird weight and stocking density, are reasonably well known, the reasons for its high incidence and severity in extensive systems are not fully understood. However, extensively reared chickens in small houses with large popholes often experience wet conditions outside and cold ones inside, so that they bring moisture into the houses on their feet. This can result in wet litter which, combined with the burning effect of ammonia from urea in the faeces in the litter is known to cause FPD and consequent poor welfare. Also, wet litter not only induces FPD but also reduces overall welfare, technical performance, and carcass yield in broiler chickens (Jong et al., 2014).

Requirements beyond those in the Broiler Directive should be assessed, developed and applied as soon as possible. FPD scoring is essential in extensive as well as intensive systems in order to address and attempt to solve the severe welfare problem of all forms of contact dermatitis (Haslam et al., 2007).

Under this heading we consider mainly liveability as a measure of bird welfare. Holt (2011) stated that “Any discussion of welfare necessitates the inclusion of mortality data for that particular housing system.  First, the liveability of a flock is a good indicator of the health and wellbeing of the birds and poor liveability suggests bird health problems.  Second, because animals generally suffer during the time leading up to death, they are experiencing a poor quality of life and therefore poor welfare status during this period.  Increased mortality stems from multiple causes such as disease, bird aggression, suffocation, and predators”.

In view of this, published data on mean mortality during the laying year has been collected and is tabulated in tables 2 – 4 below: some figures are rounded and some require explanation. The original papers should therefore be examined for more detailed information and understanding.

The categories of systems are those used in the LayWel report (Blokhuis et al, 2007) as detailed by Fiks van Niekerk and Elson (2005). CC = conventional cage,

FC = furnished cage, FR = free-range, Conv. = conventional FR and Org. = organic FR. 

* indicates the range of mortalities reported.

 Table 2: % mortality in studies across all systems for laying hens

Table 3: % mortality in studies across barn and FR systems

Table 4: % mortality in studies within conventional and organic FR systems 

The importance of mortality 

The figures tabulated above do not tell the whole story, of course, but they do show that mortality, which is recorded on most poultry farms and is a valuable indicator of poor welfare, is considerably higher in non-cage systems especially free-range ones. That was shown clearly in the study reported by Elson and Croxall, (2006), the results of which are summarised on the first line of table 2 above. This study involved assessments on 39 well managed flocks of beak trimmed laying hens of various brown feathered genotypes on farms in the UK, Germany and the Netherlands. These flocks were housed in CCs, FCs, single tier aviaries (barns), multi-tier aviaries and FR. As shown in figure 1, the cumulative mean mortality during the laying year was highest in FR (14%) and lowest in FCs (3%). The breeders’ benchmark for most brown genotypes is between 4 and 5%.

FCs were developed about 20 years ago (Appleby et al., 2002) and meet the requirements of EU Council Directive 1999/74/EC (1999). They are now widespread throughout Europe and their use is spreading to other continents. Experience with them has confirmed this low mortality, often below 3 %, generally combined with good feathering and excellent egg production (Elson and Tauson, 2012). However free range flocks have not fared so well. In the same study the mean mortality in the nine FR flocks of 14% varied between about two and 22% - see figure 2. Other large scale FR studies in Denmark (Stokholm et al., 2010;  Hegelund et al., 2006), the Netherlands (Bestman and Maurer, 2006), Sweden (Berg, 2001) and the United Kingdom (Drake et al., 2010; Whay et al., 2007) have also revealed much higher mortality than in cage systems and also large differences between FR flocks. Causes are attributed to several factors including predation, scares leading to smothering, endoparasitic infestation and infections spread by wild birds; each of these is associated with the fact hens are free to go outside and mix with wild animals rather than being kept in safe controlled conditions.

Hegelund et al. (2006) found considerable differences between regularly recorded mortality and that discovered when the number of hens depopulated was subtracted from the number originally housed. The latter was higher; they called the difference missing FR mortality and deduced that it could be accounted for by the fact that carcasses from predation and smothering seem to be removed by predators and scavengers without the awareness of stockpersons. True mortality should be calculated from the placed and depopulated numbers.

Cage v range 

Although outdoor access for hens is perceived by some to offer an improved quality of life, these risks of high mortality indicate significant negative effects on hen welfare. The European Food Safety Authority (2005) scientific opinion noted various hazards and made several welfare recommendations. Recommendation 13 was: “Efforts should be made to minimise mortality and morbidity, including the use of benchmarking and other incentives, in order to reduce the risk of poor welfare. Only those systems, in which there is expected to be low mortality, should be used”. It is difficult to see how FR in its present formcan consistently meet this recommendation (Elson, 2008). 

Commenting on the results of another major UK study of laying hen welfare in four different housing systems reported by Sherwin et al. (2010) – see second line of table 2., Nicol et al. (2009) concluded “This study did not include a detailed analysis of all hen behaviours but, considering the indicators of physical wellbeing and stress response that were measured, the welfare of hens in the FC system appeared to be better than that of hens in the other systems”.

Over 50% of UK laying hens are now kept on FR and their eggs are sold at a considerable premium over those produced by hens in FCs. During 2013 there was much debate in the UK about the welfare of hens kept in these systems. Nicol (2013) pointed out that three major potential welfare problems are more likely to occur in FR than in FCs: mortality, injurious pecking and bone fractures. Workers at Bristol University have combined measures of these three and summarised the situation for the average flock of FR hens. By the end of lay 10% of the flock will have died and of the survivors 42% will have both a bone fracture and a significant number of severe pecks; only 12% of the surviving hens will be unharmed. Having said that, as illustrated above, results from FR flocks vary greatly from one another and some (probably a minority) have good feathering and liveability. My conclusion (Elson, 2008) is that “Allowing poultry outside access increases their freedom and behavioural repertoire but it is accompanied by greater risks to important aspects of their wellbeing”.

It is difficult to achieve good biosecurity and to protect welfare sufficiently when poultry are kept in extensive housing systems. A possible approach to making FR safe from predators, avoiding contact with wild birds and animals and reducing infection and infestation would be to introduce an indoor range area as well as a protected limited outdoor wooded one. This could be achieved using a housing system such as Rondeel™, which also incorporates a multi-level aviary and natural UV light (Van Niekerk and Reuvekamp, 2011) – see figure 3. Such a system might be adapted to provide safe FR under a new definition (Elson, 2012). Its adoption, instead of outside FR as currently defined in EU Directive 1999/74/EC (1999), would leave only organic FR as a fully extensive land based system with the greatest risk of poor wellbeing. 

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