Researchers have come up with some new welfare guidelines on handling spent hens. SAC poultry behaviour and welfare scientist Vicky Sandilands shares some research on the issue.
End-of-lay hens tend to be vulnerable to bone fracture during depopulation, not least because of the high calcium demand associated with eggshell production.
Previous trials at SAC have indicated that a number of birds are damaged during the catching process. This prompted us to investigate it in more detail and look at ways of improving their welfare.
Random samples of birds, taken at the point of catching, were X-rayed to assess the level of fractures that occurred during removal. Conventional cage systems proved to be the most damaging, with 24% of birds showing new fractures. The figure for free-range and barn-egg layers was 10%, with 6% for birds from enriched-cage systems.
Housing design
Having interviewed a number of professional catching teams, our research group found workers held strong views about the relationship between housing design and bird welfare.
They reported that narrow cage doors made catching and removing birds difficult, and put forward the idea that positioning shed doors in the centre of the building would cut down the amount of time spent on carrying the birds. Other recommendations included leaving enough space for lorries to park close to the shed, and increasing aisle width in relevant systems.
With the impending ban on conventional cages due in 2012, and an expected increase in enriched-cage housing, it's worth taking note of some of the observations from our research.
We found most new wing fractures are sustained when catchers pull birds through the cage door. These openings were about 800sq cm in conventional cages, and from 1400-1800sq cm in enriched systems.
In general, wider cage door openings resulted in fewer new bone fractures. But in one case, where a conventional cage system had 1100sq cm openings, some catchers pulled more than one bird through the gap, to speed the process. That led to a greater than expected level of damage.
The research findings supported the DEFRA code of practice recommendations to catch one bird at a time. With enriched cages, two catchers per cage should be employed, perhaps using a panel, or even an empty feed bag, to create a barrier. This would reduce the available area for catching the birds, and help to prevent injuries.
Handling end-of-lay hens
Most catchers were careful to implement guidelines on handling end-of-lay hens, catching one at a time, and holding the birds by both legs. But these welfare considerations were sometimes compromised, especially when they were short of time, or when the catching team included unskilled labour.
All the employees we interviewed understood the importance of catching and carrying birds by two legs, but in some cases this didn’t happen in practice. This was possibly due to time constraints. Lorry drivers have legal limits on working hours, so the amount of time spent at the unit was restricted. This meant that catchers sometimes had to complete loading within set periods.
One example observed was when the catching crew started out by carrying birds by both legs. About half way through depopulating the flock, the catching organiser ordered the team to revert to carrying hens by one leg, to save time.
It was a very warm day, and the birds were being depleted during the mid-afternoon. The perceived benefit of speeding up the process was that catching the birds by one leg meant that, overall, birds would remain stationary on the vehicle for less time. There were also concerns that the driver must not exceed the legal daily working limit.
Light intensity
The research also revealed an association between light intensity before catching and stress suffered by the birds. This was measured by testing blood samples for corticosterone levels, which indicate a short-term response to stress.
The general advice is to reduce lighting levels at least two hours before depopulation begins. In barn and free-range systems, this should be 10 lux or less at bird head height. Meanwhile, birds will further benefit if the area nearest to the catching door is even darker. This can be achieved by removing the light bulb above the gathering area. For cage systems, it is better to restrict lighting intensity to a maximum of 5-10 lux at trough level.
Catcher experience
The job of a catcher often involves difficult working conditions. But the benefits of hiring experienced catching teams should not be underestimated, as they are more likely to handle the birds correctly.
When we interviewed catching teams, we were told that cage systems were considered poor, in terms of bird welfare during depopulation. Welfare was thought to be particularly compromised during the depopulation of cage systems, if the number of tiers exceeded three.
But cage systems were perceived to have a negative effect on the workers themselves, mainly because of the problems met during bird removal, an activity which had resulted in personal injury on occasion. Most catchers said they preferred to work in barn and free-range housing.
The stresses on poultry catchers have received little attention in the past. But it is logical to assume that making conditions easier for the teams is also likely to improve bird welfare.
There may not currently be forthcoming legislation that will turn guidelines into compulsory procedures. But DEFRA’s recommendations include a maximum three birds per hand, and the use of both legs for carrying, as well as supporting the breast during cage removal. Loose-housed birds should be handled using both legs, says the code.
While there is no new financial incentive for producers or catchers to make any adjustments to housing or working practices, the public are asking more questions about the way food is produced.
It can only be good for the industry’s future if workers aim to minimise stress and damage within flocks. At present, the best way to achieve this goal is for producers and catchers to follow the Joint Industry Welfare Guide to the Handling of End of Lay Hens and Breeders (PDF).
Keel bone damage
Future work at SAC will focus on fractures – particularly to the keel bone – sustained during the laying cycle by birds in extensive systems. This type of injury is harder to address than wing or leg damage, because it is not easy for the producer to spot the symptoms.
We will examine the potential economic impact of keel bone damage. Hens can be clumsy, especially when descending, and these injuries are far from rare, particularly in housing which gives the birds freedom to move around. One possible option for improving the statistics is to select from strains with a stronger bone structure, without loss of productivity.