Performance of injected RFID transponders to collect data about laying performance and behaviour of hens

In order to evaluate existing commercial strains many systems that automatically collect data about laying performance and behaviour of hens, reared in alternative housing systems, have been developed and tested. Most of these systems identify animals through transponders fastened to legs or wings. With this type of recording systems, transponders injected into hens' feet have never been evaluated. This different location could bring some advantages. Reducing the operational distance between the transponder and the reader, this transponder location could improve the performance of the resulting recording system. Aim of this study was to carry out a preliminary test on the use of feet-injected transponders to collect data about laying performance and behaviour of hens for breeding programs. Two experimental nesting systems (N1 and N2), similar to those already developed by other authors, were tested and used to evaluate this different transponder location. Field tests involved two experimental groups of hens (G1 and G2, of 10 hens each). For each hen in the experimental group G1 a transponder was tightened to its leg through a leg band. For each animal of the experimental group G2, a transponder was inoculated into the interdigital portion of each hen's right foot. Field tests were carried out for two months (i.e. eight weeks) following a cross design (i.e. G1 in N1 and G2 in N2 for the first four weeks - G1 in N2 and G2 in N1 for the following four weeks). During the experiment, when a hen entered in a nest: (1) it was identified through its transponder, (2) the laid egg was registered by photo cells when it rolled out from the nest box and (3) the egg-to-hen assignment was performed by the experimental nesting system. At the end of the day, eggs from each nest's collecting tube were manually picked up and assigned to a specific animal, according to the data recorded. Video recordings, captured from the nest interior by each "nest usage sensor", were also analysed. Through these video recordings, 1120 nest visits by hens were evaluated (560 for each experimental nesting system). Through comparisons between the time-stamps of video recordings and the time-stamps of data stored by the experimental nesting systems, the times necessary to identify hens were identified. These values (i.e. the animal identification speeds) were used to evaluate the performances of the two different transponder' locations compared. Results showed that the use of feet-injected transponders could bring a possible improvement in hens' identification speed (4.52 sec. in case of hens with leg band Vs. 3.44 sec. in case of hens with feet-injected transponders). Accordingly, data recorded from systems that automatically collect data from laying performance and behaviour of hens would be more accurate if this technical solution would be adopted