Microinjections of the dopamine agonist apomorphine into the nucleus basalis prosencephali of pigeons elicit stereotyped pecking behaviour. Injections of 6-hydroxydopamine, a toxic dopamine antagonist, into the same nucleus impair stereotyped pecking induced by systemic apomorphine administration, but do not interfere with pecking in the normal feeding context.

The production and coordination of rhythmic activities in birds is seldom investigated. Here we describe the pecking and breathing rhythms of pigeons under different conditions. When feeding from a heap of small grains, hungry pigeons pecked at regular intervals of about 0.3 s. The pecking rhythm was slightly slo,":,er in the afternoon. The pecking rhythm induced by the dopaminergic drug apomor...

Asymmetric information models predict a “pecking order” which reflects a combination of owner-manager preferences and external capital supply constraints whenever insiders know more about the true value of the firm’s prospects than outsiders. The pecking order results in retained earnings being the most preferred source of finance, then debt and finally the issue of new shares to outsiders. Usi...

We quantify the empirical relevance of the pecking order hypothesis using a novel empirical model and testing strategy that addresses statistical power concerns with previous tests. While the classificatory ability of the pecking order varies significantly depending on whether one interprets the hypothesis in a strict or liberal (e.g., “modified” pecking order) manner, the pecking order is neve...

Free radicals are species with one or more unpaired electrons. The unpaired electron results in a species that is often highly reactive. Free radicals have a wide range of reactions; two broad classes of reactions are electron transfer and addition reactions resulting in covalent bond formation. Free radicals can be classified as reducing (donating an electron to an acceptor) or oxidizing (acce...

introduction the commercial egg industry commonly uses induced molt procedures to rejuvenate flocks for a second or third laying cycle. molting may be induced by feed withdrawal for up to 10 days (7), water withdrawal for 2 days (19), or both, along with a reduction of day length (14). such programs cause concern about animal welfare because it is thought that they may be harmful to hens (28). ...

Both stocking rate and housing systems are main factors influencing the occurrence of feather pecking in laying hens raised in conventional cage system. This study examines the effects of different type of cage and stock density on feather pecking behaviour in hens. Total of 216 Hisex Brown hens at 16 weeks of age were randomly selected and put into 2 types of battery cages: conventional cages ...

1. The aim was to test whether provision of foraging material and food form influence feather pecking and feather damage in laying hens. 2. From week 19 of age, 16 groups of 11 hens (white Lohman Selected Leghorn hybrids) were kept in pens with or without access to long-cut straw as foraging material and fed on either mash or pellets. 3. Foraging behaviour was increased in hens with access to s...