the present study was designed to investigate the prevalence of salmonella species, their molecular characterization and antibiotic resistance in backyard chickens. a total of 1125 samples were collected from backyard chickens in two consequent samplings. in the first part, samples were included of 820 poor recently hatched chicks, hatching residuals, egg shells in the nest floor, cloacal swabs...

1. To evaluate the effect of primary in vitro antigenic stimulation on a population of immunologically competent cells, a homologous cell transfer system was used, with adult chickens as the spleen cell donors, killed Brucella abortus as the antigen, and newly hatched chicks as the recipients. 2. The distribution of antibody titers in recipients of cells from random donors was bimodal, with abo...

A large body of literature shows that non-human animals master a variety of numerical tasks, but studies involving proportional discrimination are sparse and primarily done with mature animals. Here we trained 4-day-old domestic chicks (Gallus gallus) to respond to stimuli depicting multiple examples of the proportion 4:1 when compared with the proportion 2:1. Stimuli were composed of green and...

INTRODUCTION Tonic immobility (TI) is fear-induced freezing that animals may undergo when confronted by a threat. It is principally observed in prey species as defence mechanisms. In our preliminary research, we detected large inter-individual variations in the frequency and duration of freezing behavior among newly hatched domestic chicks (Gallus gallus). In this study we aim to identify the c...

Newly hatched domestic chicks were reared with five identical objects. On days 3 or 4, chicks underwent free-choice tests in which sets of three and two of the five original objects disappeared (either simultaneously or one by one), each behind one of two opaque identical screens. Chicks spontaneously inspected the screen occluding the larger set (experiment 1). Results were confirmed under con...

Avian hepatitis E virus (HEV) is genetically and antigenically related to human HEV. Vertical transmission of HEV has been reported in humans, but not in other animals. In this study, we showed that avian HEV could be detected in chicken egg-white samples. Subsequently, avian HEV in egg white was found to be infectious, as evidenced by the appearance of viraemia, faecal virus shedding and seroc...

Colonization of the intestinal tracts of newly hatched chicks with Escherichia coli was attempted by swabbing test organisms onto the air-shell of 19-day-old embryos. Test organisms consisted of two virulent E. coli isolates, one avirulent isolate, and one laboratory-derived mutant of the avirulent isolate carrying a recombinant plasmid coding for Colicin V production. Chicks were cultured week...

Domestic chickens (Gallus gallus) can be trained to search for a social stimulus in a specific magnetic direction, and cryptochrome 1a, found in the retina, has been proposed as a receptor molecule mediating magnetic directions. The present study combines immuno-histochemical and behavioural data to analyse the ontogenetic development of this ability. Newly hatched chicks already have a small a...

For all species, finite metabolic resources must be allocated toward three competing systems: maintenance, reproduction, and growth. Telomeres, the nucleoprotein tips of chromosomes, which shorten with age in most species, are correlated with increased survival. Chick growth is energetically costly and is associated with telomere shortening in most species. To assess the change in telomeres in ...