The behavioural priorities of laying hens: the effect of cost/no cost multi-choice tests on time budgets.

A multi-choice situation offering a number of presumably significant environmental features may reveal an animal's immediate preferences concerning its environment and how it wants to distribute its time budget. In this study the time budgets of hens (Gallus gallus domesticus) were examined in a free access situation (no cost condition) and in a situation in which there was a cost for access (cost condition). The options consisted of six pens that could be entered from a middle pen which had no features except for space. The options were: (1) food and water; (2) woodchips; (3) grass (turf) or wheat seedlings; (4) a perch; (5) a nestbox; (6) a pen facing another pen with familiar hens. In the first experiment, hens were given a multi-choice test in a seven pen apparatus. The no cost condition gave free access to resources but in the cost condition hens had to squeeze through two dowels. The frequency of entering pens and initiating behaviours was greatly reduced in the cost condition. In the second experiment, hens were tested for their preferences after one of two treatments: (i) 'prior access' (and free access) to all pens for 22.5 h; (ii) 'no prior access' where hens were housed in a barren pen without food for 22.5 h. The duration of agonistic, pace/escape and stretch neck behaviours were greater in the 'no prior access' or cost condition. In both experiments, the amount of time pecking and scratching in litter did not differ between conditions. Thus, the imposition of a cost did not alter the amount of time spent pecking and scratching supporting the argument that this behaviour is an ethological need.