Behavioural differences in laying hens with and without “Llovera method” during spring.

Abstract

An environment with no flies and the presence of free hens could originate a special ecologic situation with influences on the improvement of productive and behavioral parameters. To analyze this hypothesis it was decided to observe, to register and to evaluate behavioral patterns that could suffer variations in the group of animals kept under Llovera´s method (hens on floor being 10% of the caged ones) compared with control animals kept in cages as in the Traditional Method (no hens on floor). A 15 minute individual observation of 24 randomly selected hens was made in a hen house where 2,000 red-colored laying hens were caged before (as control group C) and after (as Llovera group J) delivering discarded hens on floor. The behaviour register was made on designated lists for the purpose. The ethogram of the animals of both groups was made by means of an ad-libitum sampling to identify behavioral patterns expressed in the conditions of the study and a focal sample to evaluate the presentation frequency of each conduct. The test of Shapiro-Wilks was used with the results obtained to verify the normality of the differences. From these results Student´s Test was used on paired samples with normal distribution, and Wilcoxon and Sign Tests for the others. This preliminary report includes results corresponding to spring season.The behavioral patterns studied in groups C and J correspond to: kinetc behavior (to extend a wing or a leg), exploratory (to scrape on floor, to look around, to peck the cage), alimentary (to eat, to drink, to regurgitate), antipredatory (to vocalize, to suddenly be quiet), agonistic (to peck on neighbor caged hen), grooming (cleaning of feathers with the beak, scratching with the leg), eliminatory (excreta evacuation), rest (to lie down with the head on the body, to flex a leg ). The Test of Shapiro-Wilks showed that “to extend a leg”, “to scrape” and “cleaning of feathers” have normal distribution. From these results t Test is used on paired samples, under the hypothesis that the mean of such differences among the observations made before regarding to those made after is higher than 0 (zero). Significative differences are not observed at 5% being the resultant means lesser or equal to 0 (zero). Other variables were analyzed using the Test of Wilcoxon for paired samples because of the lack of normality. The variables were: “to drink”, “to be quiet”, “pecking”, “to evacuate” and “to look”, with significative differences at 5% existing a lesser presentation in the Group “J” regarding the “C”. The presence of free hens on floor and the consequent decrease in the number of flies were the only differences in production conditions between the Groups “C” and “J”. So, the modificatios in the behavior of each group should be attributed to those conditions. The higher frequency of some of the studied patterns before placing hens on floor would show that the presence of them modifies the behavior of caged hens. However, it is necessary to complete the analysis of the corresponding data of the other seasons of the year to conclude on the influence of these changes on the animals´ welfare.