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The welfare effects of different methods of depopulation on laying hens. - AW0231

This proposal will inform policy by providing representative, contemporary data on the potentially adverse welfare effects occuring at the time of depopoulation of end-of-lay hens. The study will be structured in two parts. The first phase will involve the gathering and analysis of data while the second phase will be used to implement, assess and report on improved practices. Initially a risk assessment appraisal of the depopulation process for both cage and non cage units will be carried out. Apart from a physical inspection of the units, following the risk-assessment analysis, the depopulation of up to 10 cage units (e.g. 7 units with enriched cages and 3 units with cages that will conform with EU Directive 99/74 on 1 January 2003) will be monitored. Data to be gathered at depopulation will include: a) noise (decibel) level in the unit due to alarm calling at regular intervals throughout depopulation; b) the tier from which the bird to be examined was removed; c) plasma corticosterone level; d) the number of fresh bone breaks; e) tonic immobility index and f) bone strength will be determined using 3-point bending test. Similarly the depopulation of 12 non-cage units will be monitored. The data will be analysed and improved protocols detailing best practice will be produced. These improved depopulation schedules will be implemented for the depopulation of 2 enriched cage units, 3 conventional cage systems and 3 non-cage systems (e.g. free range/barn system incorporating raised perches, free range/barn unit using slats as perches and deep litter units). Data will be gathered during depopulation and analysed as before. It is anticipated that the information gained will be used to develop improved depopulation strategies to minimise adverse welfare problems.
01: To identify through a risk-assessment of production units and depopulation practices, the key features that are likely to have a significant impact on the welfare of laying hens at depopulation.
02: To gather data on the welfare insults inflicted on laying hens when depopulatated from traditional cage and enriched cage systems.
03: To gather data on the welfare insults on laying hens whene depopulated from non-cage systems.
04: To analyse the data from Objectives 2-4 and compile information note on the indicators of adverse welfare effects of laying hens during depopulation.
05: To devise improved protocols for the depopulation of laying hens from caged and non-cages units.
06: To test improved protocols for the depopulaton laying hens from caged and non-caged units.
07: To analyse the data from Objective 7 and produce recommendations on best practice for the depopulation of laying hen units.
Project Documents
• Final Report : The welfare effects of different methods of depopulation on laying hens   (4149k)
• Final Report - Annex : The welfare effects of different methods of depopulation on laying hens   (552k)
Time-Scale and Cost
From: 2003

To: 2005

Cost: £144,534
Contractor / Funded Organisations
University - Scottish Agricultural College
Animal Welfare              
Livestock Farming              
Fields of Study
Animal Welfare