As result of the EU Council Directive 99/74/EC of 19 July 1999 laying down minimum standards for the protection of laying hens, the use of the conventional cage system is prohibited since the 1st of January 2012 in the European Union member countries. Simultaneously, in some of the member countries (for example: Denmark, Finland, Sweden and Germany) the beak trimming of the laying hens – which is momently allowed till 10 days of age in the European Union – is also prohibited, while in some other member countries (for example: United Kingdom, France and Netherlands) its prohibition is being considered.
Stopping the beak trimming in laying hens could improve the mortality in the farm in case the current genetic programs remain in use. Therefore, the present aim of Bábolna TETRA Ltd. is to develop a new hybrid, which is able for high production in alternative housing systems without beak trimming. As first step of this development, non-debeaked layers from 4 lines of the TETRA breeding program were tested in order to compare the changes in their plumage and body condition during the first egg-laying period.
The hens’ body condition (body fat content) was determined by means of computer tomography (CT) in vivo at the Institute of Diagnostic Imaging and Radiation Oncology of the Kaposvár University. Before the CT measurements the live weight of the hens was always recorded. During the CT scanning procedures birds were fixed with belts in a special plexi-glass container, without using any anaesthetics. Three animals were scanned simultaneously (Image 1). Due to the special
On Figure 1 it can be seen that the plumage condition of Line 1 was the worst during the whole examined period. The total plumage point was significantly lower already at the start of the egg production in this line than in the others (P<0.05). While the Lines 2-4 had almost fully complete plumage (Image 3) at 20 weeks of age (average total plumage points between 19.4 and 19.7), the plumage of the hens in Line 1 was strongly damaged (Image 4) already at this age (average total plumage point 16.7). While total plumage points under 18 were not observed in Lines 2-4, thirteen hens of Line 1 had total plumage points between 11 and 17 and none of them had 20 points at this age.
As it is visible on Figure 2, also the body condition of the hens was the worst in Line 1 during the whole experimental period. In this line the body fat content of the hens decreased by 14.5% between the start and the end of the experiment.
From these results it can be seen that the worst body condition was observed in the line with the worst plumage condition, while the best body condition was recorded in the line with the best plumage condition. Therefore, it can be concluded that the occurrence of feather pecking in non-debeaked laying hens results not only in damages in the plumage condition, but also in decreasing the body fat content, i.e. in failure of the body condition. Therefore, for maintaining the high production level also in non-debeaked layer flocks, selection of the hens (lines, families, individuals) for calm temperament seems to be very important in the future.
References
Tauson, R. – Kjaer, J. – Maria, G.A. – Cepero, R. – Holm, K-E. (2006): Welfare implications of changes in production systems for laying hens. Work package 3. Final report health, D.3.1. The creation of a common scoring system for the integument and health of laying. Specific Targeted Research Project (STR eP).