Stress responses in laying hens were mediated by continuous infusion of adrenocorticotropin (ACTH) via osmotic pumps. The ACTH was dissolved in saline solution (0.85%), and each pump delivered 8 IU of ACTH per kilogram of BW per day at the rate of 1 uL/h for 7 d. Control hens received pumps loaded with saline. Measurements …
Fear can be a damaging stressor, resulting in impaired animal welfare and poor production economy. Often fear reactions are elicited in situations that are in some way related to predator defence. As males have a guarding role, mixing the sexes might be a way of reducing fear in large groups of laying hens. Tonic immobility …
Domestication and selection for high production have selected animals with less energy-demanding behaviour. In the natural environment of the ancestors, fitness (reproductive success) is often favoured by an ability to locate and remember food sites, whereas in captivity, fitness may be more related to the ability to grow and reproduce efficiently under stable food conditions. …
Fear is now widely regarded as an undesirable state of suffering by many members of the public, the scientific community, welfare and policy groups, as well as by a growing number of farmers. At first glance this view appears to be inconsistent with one based on biological significance, in which fear is regarded as an …
1. Over twelve 28-d laying periods (almost one year), 272 laying hens of the Lohmann Silver strain, individually tagged with transponders, were monitored on their ranging behaviour and laying performance in an aviary system with an adjacent winter garden. 2. From laying periods 1 to 12, the daily frequency of passages between the barn and …
Tests assessing the fear of humans by measuring avoidance or approach reactions of the test animals towards humans can be useful tools in welfare assessment schemes. In this study, we wanted to compare tests assessing the reactions of laying hens towards humans in the home environment to a test performed in a novel environment. As …
1. This trial studied the effects of strain and age on tonic immobility (TI) duration, emergence time (ET) and social reinstatement time (SRT) in laying hens and investigated the consistency of individual behavioural characteristics over rearing and laying periods and the correlations between these behavioural traits. 2. One hundred chicks from each of ISA Brown …
1. Physiological and behavioural measures of stress in caged hens on a commercial farm were compared between White Leghorn and brown Hyline strains, and between three tiers of cages. 2. Blood and faecal samples were collected from undisturbed birds for corticosterone measurements. Plasma corticosterone responses to a stressor were measured by the collection of blood …
Domestic fowl (Gallus gallus domesticus) naturally live in small groups, with a dominance hierarchy (pecking order) which is most likely based on establishment fights, followed by remembered assessment of status involving individual recognition. In larger groups, this system is thought to break-down, and hens may adapt by becoming less aggressive, or by restricting their movements …
White Leghorn chickens were genetically selected for high (HGPS) or low (LGPS) group productivity and survivability. The selection resulted in two genetic lines with marked opposite changes in cannibalism and flightiness when housed in multiple-colony battery cages without beak trimming. The objective of the study was to examine whether the genetic selection differentially affected the …
Four layer genetic stocks consisting of 3 Ottawa control strains (5, 7, and 10) and a commercial laying stock (CCS) …
Experimental research was carried out with laying hens of 47-60 weeks of age to validate a physical model of the evaporation rate of water from litter in a tiered wire floor aviary system. Variation of the evaporation rate of water from the litter was achieved by varying air velocities above the litter between 0.07 and …
The effects of a litter drying system are reported on the composition of the litter and the emission of ammonia from a tiered wire floor aviary housing system for laying hens. Air velocities above the litter, a mixture of droppings and sand, were increased by means of air that was sucked from the top of …
1. Sixty-three laying hens were collected from 5 commercial farms experiencing outbreaks of cannibalism. It is known that cannibalistic behaviour varies strongly between hybrids and between individuals of the same hybrid. The aim of this study was to test specific hypotheses about the causation of cannibalism by comparing matched individuals varying in their cannibalistic behaviour. …
1. Mortality and causes of death were recorded over two trials with 13 045 Lohmann Selected Leghorn (LSL, white layer strain) and 4410 Lohmann Brown (LB) laying hens kept in furnished small group housing systems and furnished cages. In trial 1, hens were housed from weeks 19 to 71 (LSL) and 17 to 69 (LB). …
The distribution of cannibalism cases in a flock of 19,776 Babcock White Leghorns was monitored from 21 to 54 wk of age. The hens were kept in a single floor house consisting of four banks of two-deck stairstep cages. Each of the 4,944 cages held four hens at a density of 152 cm2 (60 inches2) …
We examined effects of being moved and mixed with strangers on the incidence of aggression and cannibalism in caged White Leghorn hens with intact beaks. We predicted that mixing of strangers would increase rates of aggression and cannibalism. Hens were reared in 16 stable groups of four birds together since hatch. At 18 months of …
In young pullets, long bones elongate by endochondral growth. Growth plate chondrocytes proliferate, then hypertrophy, and are replaced by osteoblasts that form a network of trabecular bone. This bone is gradually resorbed by osteoclasts as the bone lengthens. Long bones widen, and flat bones are formed, by intramembranous ossification in which cortical bone formation by …