Social preferences in Japanese quail chicks from lines selected for low or high social reinstatement motivation: effects of number and line identity of the stimulus birds

Divergent lines of Japanese quail which have been genetically selected over several generations for high (HSR) or low (LSR) levels of social reinstatement (SR) behaviour show corresponding differences in underlying social motivation (sociality), Because sociality is a particularly influential behavioural trait in precocial species, such selection may have important implications for poultry welfare and performance. However, we must first establish whether it might influence other important behavioural characteristics or capabilities, such as social discrimination. The present study compared the social preferences of LSR and HSR quail chicks for same- and different-line birds presented either singly or in small groups. Thus, the responses of individually tested chicks of both lines were compared in a two-choice runway test when the opposing goal boxes contained either 1 HSR vs. 1 LSR or 5 HSR vs. 5 LSR stimulus birds. More HSR quail moved first towards chicks of their own line than towards LSR ones, they approached HSR quail sooner and spent longer near them regardless of whether the stimulus birds were presented singly or in groups. Conversely, apart from moving towards same-line birds first when they were presented singly, LSR quail exhibited no social preferences. These findings provide clear evidence of line discrimination in HSR quail but it is not yet known if the responses of LSR birds reflected impaired discrimination, increased attention to the novel features of the test environment, or a simple lack of this particular social preference. (C) 1998 Elsevier Science B.V. All rights reserved.