for the RFID registrations. To achieve a minimum sensitivity of
85% a time window size of 31 s was needed for the average tag.
Specificity was always larger than 85% (data not shown). Sensitivity
of individual tags varied between 37% and 100% with a time
window of 31 s. For some tags a sensitivity of 85% was already
reached for a time window of 5 s, while for others this was not
even reached at a time window of 51 s. This indicates that the different
tags had different time gaps between their RFID registrations
during feeding. A large difference in performance between
the left and right tag of the same pig could sometimes be observed.
Technical performances of the tags, position and orientation of the
tags during feeding and specific pig behaviours (e.g. preference for
a certain side at the feeder) could possibly explain the differences
in sensitivity of the two tags on the same pig.