Occurrence, causes and consequences of keel bone damage of laying hens

Abstract

Keel bone damage (KBD) is a multifactorial problem. This problem applies to all types of housing systems, caged as well as cage-free systems, including free-range and organic. The common causes are in particular collisions with the elements of the environment, such as perches, as well as collisions between hens. Extremely high frequency and severity of damage adversely affects not only welfare of laying hens also their production and egg quality too. This article provides an overview of current knowledge about the occurrence of KBD, the causes of its occurrence and consequences for the quality of life of laying hens in intensive large-scale production conditions. In the introductory part, we describe what keel bone is, the high incidence and prevalence of the problem, which implies the importance of long-term dealing with this issue at the global level. In the next part, we deal with the factors that can cause the occurrence of KBD, the relationship between the occurrence of KBD and bone quality, nutrition with an emphasis on calcium, the relationship between KBD and welfare, individual housing systems, age, genotypes of hens, feathering, efficiency and quality of production of laying hens and in the final part section we present detection methods. As already mentioned, the occurrence of KBD is influenced by a number of factors, but due to the differences in the prevalence of this problem in different countries, further comprehensive research is needed. The deviations and fractures of the keel bone can have a negative impact on the welfare of laying hens, which will subsequently be reflected in the possible painfulness of feed intake, laying, product quality, which ultimately will always affect economic efficiency. The goal of long-term research should to try to reduce the incidence of these conditions, or their prevention. It is important to deal with genetic selection, nutrition, a very important area, as far as KBD is concerned, are the conditions of the breeding environment, especially the housing system and the elements that make up the equipment of the rearing and breeding area, as well as the standardization of the methods used to detect damage to the keel bone. Palpation, post-mortem palpation, multiple sensing technologies are used. Researcher training can significantly improve both the accuracy and reliability of assessment of sternal fractures and deviations. If the results of keel bone prevalence will be compared or combined between individual studies, all methods used to detect keel bone damage should be accurate, i.e. sufficient methodological details should be given for each study and the method of determining prevalence should be standardized.