1. The aim of the present study was to investigate whether individual birds specialise in feather pecking. Growers were individually marked and reared in groups of 30 or 31 in pens with a slatted floor. At an age of 4 to 6 weeks feather pecking was frequent in all pens. 2. On average 83% of all group members (10 groups, experiment 1) were recorded at least once as initiator of a feather pecking...

Dextromethorphan is an NMDA receptor antagonist in the glutamatergic system. Currently, there are some reports showing that the glutamatergic NMDA receptor mechanism stimulates dopamine release from several brain regions. This effect may in part modulate the stereotyped behaviors of dopaminergic system. The purpose of the present study was to determine the interaction between the blockade of NM...

The objective of the current study was to estimate heritabilities (h2) of feather pecking and open-field response of laying hens at two different ages. An F2 cross, originating from a high and a low feather pecking line of laying hens, was used for the experiment. Each of the 630 birds of the F2 cross was subjected to an open-field test (individual, 10 min) at 5 and 29 wk of age and to a social...

Severe feather pecking (SFP) in chickens is a detrimental behaviour with possibly neurochemical deficits at its base. Recent neurological studies depicted conflicting results on the role of serotonin (5-hydroxytryptamine, 5-HT) and dopamine (DA) in the development and display of feather pecking. We studied brain monoamine levels and behaviour in domestic chickens divergently genetically selecte...

The role of the nucleus basalis prosencephali (Bas), a frontal forebrain structure peculiar to birds, in the control of forage pecking and apomorphine-induced pecking was investigated. In a quasi-natural grit-grain selection task bilateral coagulations of the Bas and the associated neostratum frontolaterale (Nfl) caused a marked fall in grain per peck uptake and a simultaneous increase in grit ...

The pecking and peeping behavior of isolate, pairand group-reared chicks tested singly with and without mirrors were studied during 2-hr tests. Results supported the hypothesis that the social facilitation of pecking is disrupted by test novelty (discrepancy between testing and rearing conditions). Mirror exposure resulted in the greatest enhancement of pecking and least peeping in pair-reared ...

This experiment investigated effects of environmental enrichment and beak-trimming during the rearing period on behavior in rearing and plumage damage later in life. Treatments were applied in a 2 × 2 factorial arrangement. Half of the birds were beak-trimmed at 1 d of age using an infra-red laser. A follow-up light-trim was performed at 11 wk of age with a hot blade. Environmental enrichment c...

The aim of this experiment was to study the relationship between feather pecking and ground pecking in laying hens and the effect of group size on feather pecking behaviour. Hisex White hens were kept in floor pens in group sizes of 15, 30, 60 and 120 birds, each with four replicates. Behavioural observations were performed at four different ages and focused on the number of feather pecks and a...

The pecking order hypothesis predicts that equity costs exceed debt costs when managers require outside funding. Asymmetric information costs motivates this hypothesis. I use an econometric model to estimate issuance costs managers face to test the prediction and motivation of the pecking order. The estimates challenge the existence of a pecking order. First, debt costs increase from about 50% ...

Broiler feeding is an efficient way of evaluating growth performance, health, and welfare status. This assessment might include the number meals, meal period, ingestion rate, intervals, proportion time spent eating. These parameters can be predicted by studying birds’ pecking activity. The present study aims to design, examine, validate classifying algorithms determine individual bird patterns ...