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By Wiebke Icken , and Dr. Rudolf Preisinger, Lohmann Tierzucht, Cuxhaven, Germany
With the aid of a new transponder technology, the free-range behaviour and laying performance of layers can be tested simultaneously. Lohmann Tierzucht, together with the Bavarian State Research Centre in Germany, investigated the laying behaviour of 272 Lohmann Silver hens in Electronic Pop Holes (EPH) and Funnel Nest Boxes (FNB).These systems made it possible to record automatically each separate visit to the free-range area as well as the egg number by every single hen in the flock. The hens were housed in an aviary with an adjoining winter garden at the Thalhausen experimental station of the Technical University of Munich. To identify each single hen in the EPH and FNB, every hen was tagged with a transponder on one leg. During the whole investigation period of one year, the winter garden was continuously accessible for the hens.
The frequency of passages (number of passages between the in- and the outside area) and the duration of stay in the free-range area of each hen was recorded daily. A large fraction of the hens (35%), did not use the winter garden at all. They were not even once registered at one of the four EPH throughout the whole year. The percentage of hens that used the winter garden (at least once in a 28 day period), increased during the observation period. As soon as a hen was familiar with the winter garden, she visited the free-range area nearly every day. Expected effects, like a reduction of the share during autumn and winter, were not found.
Antagonistic trend
The highest number of passages through the EPH was registered in the second laying period (15 passages per hen per day). Thereafter, the frequency decreased from a level of 13 passages in the fifth laying period to eight passages in the 12th laying period. The average length of stay in the winter garden showed an antagonistic trend to the frequency of passages. At the beginning of the observation period, the average visit to the winter garden had a duration of 14 minutes, whereas from laying period seven to the end of the observation, a single stay took an average of more than 30 minutes.
The highest number of passages through the EPH was registered in the second laying period (15 passages per hen per day). Thereafter, the frequency decreased from a level of 13 passages in the fifth laying period to eight passages in the 12th laying period. The average length of stay in the winter garden showed an antagonistic trend to the frequency of passages. At the beginning of the observation period, the average visit to the winter garden had a duration of 14 minutes, whereas from laying period seven to the end of the observation, a single stay took an average of more than 30 minutes.
The number of passages and the duration of stay in the winter garden showed a big variation from hen to hen. There were some hens which returned to the barn after a short glance into the winter garden, whereas others stayed nearly day and night outside. Most of the passages through the EPH were registered in the morning between 6 am and 8 am as well as in the afternoon between 4 pm and 5 pm. The average stay in the winter garden per hen per day was about 2.5 to 4 hours. At four o’clock in the morning, the artificial light in the barn was switched on and at 8 pm, it was switched off. From 8 am onwards, the hens were looking intensively for the FNB to lay their eggs. The laying performance of the hens were calculated for each 28-day laying period, beginning with the first correct registered egg in the FNB.
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Source: World Poultry, Vol. 27, No. 4, 2011
