Solutions to improve laying hen welfare
Project Lead
Challenges
Chickens are one of the most numerous farm animals in the world and provide a valuable food source to people with many dietary requirements. The only permitted form of cage housing for commercial laying hens is enriched cages due to the ban on conventional cages in 2012. However, this housing system is falling out of favour due to the limit cage type places on expression of behaviours.
In the UK, the major retailers intend to stop stocking shell eggs from caged hens by 2025. The current proportion of eggs produced in cages will decline and need to be produced as barn, free-range or organic eggs. Despite the benefits of these housing systems, hens may still experience feather pecking, keel-bone fractures, and forced housing of free-range (and organic) hens during disease outbreaks.
Feather pecking
Despite decades of research, commercial laying hen flocks still suffer outbreaks of feather pecking and cannibalism. This is particularly true in large group housing systems, such as free-range and barn. To reduce the damage caused by injurious pecking, layer chicks are routinely infra-red beak trimmed at the hatchery. The UK is looking to move away from this practice. Instead, injurious pecking is prevented through better management and the genetic selection of hens.
One of the key drivers of feather pecking is the lack of suitable foraging material. Hens are highly motivated to show lengthy food-seeking behaviours to fulfil the appetitive phase of eating. Providing extra enrichment in non-cage housing systems has inconsistent results and further research in this area is recommended. One edible item that could be included in the litter is sprouted grains. Sprouted grains release enzymes that increase the digestibility of the grain, plus provide greater levels of carotene. Carotene improves (darkens) yolk colour, while the small green sprout remains small enough not to impact the crop. Early studies on sprouted grains have been reported to improve feather growth.
Keel-bone fractures
The proportions of hen flocks with keel bone damage are known to be higher within loose-housed (barn, free-range and organic) cage systems. While keel bone deviations may not be painful, evidence suggests that keel-bone fractures (KBF) are based on the self-dosing of analgesics and behaviour. Further exacerbating KBF prevalence is that loose-housed systems are often fitted with multi-tier structures in which hens must negotiate the 3-D space to reach resources on different levels. With growing evidence of the high prevalence of KBF in these systems, there has subsequently been considerable research looking at ways of reducing KBF prevalence. However, this evidence needs to be practical for producers to implement and demonstrated to be effective.
Forced housing of free-range hens
Free-range egg systems (including organic) made up 57% of eggs produced in the UK in 2020. With the move of retailers away from cage eggs, this figure is bound to increase in future years. Free-range hens normally have daily access to the range where a notifiable disease can break out, including Avian Influenza and Newcastle Disease. Unlike Newcastle Disease, there is no useable vaccine for Avian Influenza, which has been appearing in Scotland regularly since 2006. To deal with such outbreaks, while birds at the infected premises are culled, protection (3 km radius) and surveillance (10 km radius) zones are placed around the infected premises. As a result, poultry flocks within those zones must be continuously housed, thus banning access of free-range hens to the outdoor space. Prolonged restricted access to the range, where hens formerly had access, can cause welfare problems such as agitation, outbreaks of (or worsened) feather pecking and cannibalism, aggression and more.
Questions
Solutions
Decrease the incidence and/or severity of feather-pecking
Laying hen welfare can be improved by reducing the damage caused during injurious pecking in birds selected for naturally duller beaks and by providing a useful foraging material and protein source (sprouting barley) to decrease the incidence of feather pecking. We are examining existing mandible bone and beak variation in breeding females to produce a beak assessment method to compare with existing approaches. Next, we are assessing the suitable levels of sprouting barley to be fed to hens without interfering with the layer’s mash feed intake or egg quality. We are also providing practical and effective ways of housing hens in non-cage systems that decrease the incidence and severity of feather-pecking that may enable beak-trimming to be banned without leading to a decline in welfare.
Ways of reducing keel-bone fracture (KBF) prevalence
Scottish egg producers are being surveyed on what they know about keel bone damage. We are pooling evidence for egg producers on practical and effective methods to reduce keel-bone fracture prevalence.
Alternative free-range systems for good hen welfare during housing orders
We are investigating alternative free-range systems with arrangements that enable welfare standards to be maintained during temporary housing orders (during disease outbreaks). This involves reviewing novel and under-utilised methods of housing, and the reasons why they may or may not succeed in Scotland. Egg producers are being surveyed on the (lack of) use of verandas to preserve hen welfare during housing orders. A set of guidelines for egg producers based on information on novel hen house designs and verandas is being developed.
Project Partners
Progress
2023 / 2024
2022 / 2023
In this year, our aim has been to begin work on decreasing the incidence and/or severity of feather pecking, by using two different approaches: i) selecting for duller beaks, and ii) using sprouting barley as a feed supplement.
For i) we collected head radiographs from 825 hens from two lines of breeding hens and analysed them using a method of morphometric measurement, identifying distinctly different phenotypic bone shapes (beneath the beaks). The same radiographs have been analysed for variation in beak shapes, and their possible association with feather cover and mortality. Blood samples and genotyping are complete and have been analysed. All results are being prepared for publication.
For ii), we sourced barley and designed a reliable hydroponic sprouting method. One hundred and twenty laying hens were split into 24 litter-floor pens and fed sprouted barley at 4 levels. We recorded body weight, feed intake, egg production, egg quality, feather score, and nutrient digestibility from ileal digesta collected post-mortem. The data analysis is currently underway.
The original plan was to begin 'ways to reduce keel-bone fracture prevalence' in Year 1 (Year 1-3), however due to recently awarded grants in this area, it was agreed to move this work to Years 3-5, to take advantage of new knowledge.
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