Behavioral Data Acquisition System

A UHF-RFID system was used to monitor feeding behaviors of individual broilers. The system consisted of 40 antennas (TIMES-7 A6034S; Impinj Inc., Seattle, WA), 360 tags (PT-103; TransTech Systems Inc., Wilsonville, OR), 3 hubs (IPJ-A6001-000; Impinj Inc., Seattle, WA), 3 readers (IPJ-REV-420; Impinj Inc., Seattle, WA), and 3 Python-based data acquisition systems. An antenna was placed underneath each tube feeder as described in our previous study (Li et al., 2019). All 45 birds in 4 pens (one pen per treatment) and 15 birds in each of the remaining 12 pens (3 pens per treatment) were tagged. A total of 360 birds were tagged. The light-weight RFID tags (less than 5 g for each) were placed using one simple-interrupted full-thickness throw of nonabsorbable nylon suture (Ethilon size 1), attaching the tag to the skin on midline of the ventral neck, approximately one inch from the bottom beak. Tags were applied by the attending veterinarian with care to avoid the underlying structures of the neck, as an experienced caretaker gently restrained the bird for a blood draw. As this minor procedure is analogous to a blood draw, no anesthetics were applied. Besides, before the study, a pilot study with 20 birds being sutured was conducted. Based on 14-day observation, only a couple of birds were observed preening around the tags soon after placement, and after that, there was seemingly no significant attention paid to the tags. In addition, our previous test showed that performance (feed consumption and conversion ratio) of birds wearing tags was similar to those without tags. Therefore, the suturing tag method should be suitable for the behavior study. The system registered birds eating at all feeders continuously. The tag IDs, feeding time, and feeder codes were saved into .csv files and processed in Microsoft Excel using Visual Basic for Application. The previous study reported a greater than 92% accuracy for monitoring broiler feeding behaviors through the UHF-RFID system (Li et al., 2019). Except for the operation of the RFID tags, we followed the similar setups with the previous study; therefore, the registration accuracy should be similar to the previous study as well.