Boys (toms) don’t try. Behaviour of turkeys in a Novel Object test – Influence of age and sex

Abstract

In the present study, a Novel Object test (NOT), designed for turkeys in small groups, was implemented on commercial farms (groups of ~ 5000 animals). The aim of the study was to investigate the reaction of turkeys to novelty in an on-farm setting, which is an approach to assess anxiety-like behaviour and hence might be an appropriate welfare indicator in farm animals. In a pilot study, repeatability of the test design was tested by presenting four different objects simultaneously at different age levels in poultry production. The main study tested the NOT repeatedly on one farm, fattening both female and male birds, with the aim to evaluate sex and age effects in commercial conditions. Data was recorded on three farms, keeping conventionally fattening turkeys (male and female birds), including two fattening periods for pilot studies and four fattening periods for the main study. Novel Object tests were conducted on flock level, using four different novel objects (a bucket, a ball string, a plastic rod and a beach ball). Data were collected by direct observation. The latency up to the first approach, latency up to the first peck, pecking frequency, and the number of animals approaching the object were recorded. Generalised linear mixed models were calculated. Results of the main study found a tendency for the object type to affect the latency to approach the object (F3201 = 2.5; p = 0.06), for all other parameters a significant effect was detected (all F > 2.6; all p < 0.05). Also, sex effects were found to be significant for all parameters measured (all F > 107.2; all p < 0.001), with females showing shorter latency times until the first peck and the first approach, a higher pecking frequency, and more animals approaching the object. The interaction between age and sex was found to be significant for the latency to approach (F6213 = 2.3; p < 0.05). Males showed longer latencies to approach the object in week 5 as compared to all other time points. No differences between time points were found in females. In summary, the results highlight important issues in turkeys’ reaction to novelty, which might be of interest in animal husbandry. Furthermore, results indicate, that further studies are required to validate this behavioural test regarding the interpretation of underlying motivations.