Application of open field, tonic immobility, and attention bias tests to hens with different ranging patterns

• DOI: 10.7717/peerj.8122
• Publication Date: 2019-11-25T08:19:10Z
• Authors: Dana L.M. Campbell; Emily J. Dickson; Caroline Lee
• Keywords: Tonic (physiology); Vigilance (psychology); Anxiogenic; Neophobia; Alarm signal; Stimulus (psychology)

Assessment of negative affective states is a key component animal welfare research. In laying hens, excessive fearfulness results in reduced production and increased sensitivity to stress. Fearfulness can be defined as response known threat, but anxiety an unknown threat may have similar consequences. The open field test tonic immobility are commonly applied measure hens. An attention bias that measured individual hen's responses playback conspecific alarm call the presence food was recently pharmacologically validated using anxiogenic drug confounded by typical motionless novel environment. current study used 56-week old free-range layers further assess validity differentiate ranging treatment groups comparison with tests. selected hens varied their range use patterns tracked radio-frequency identification technology. 'Indoor' did not access 'outdoor' ranged daily; previous research has confirmed higher remain indoors. (P = 0.34), indoor birds were slower first step 0.03) stepped less 0.02) test. occurred isolated wooden box (a threat) mixed grain positive stimulus). behavioural latency resume eating following outdoor birds. Before could occur, had habituated across three separate 5-minute sessions increase willingness feed within All ate faster time < 0.001) eat than 0.001). this study, determined poor for highly anxious they failed at all. Forty-six percent excluded Of eat, only 7% call, compared 36% This repetition highlights challenges assessing extreme fearful/anxious information missed when non-performing from We suggest arena without any informative state all consideration must made potential differences motivation.