The aim of the present investigation is to report the prevalence of spontaneous fractures associated with leg skeletal pathology and compromised welfare in commercial broiler chickens. Our studies focused on fractures of different leg segments (femur, tibiotarsus, tarsometatarsus) detected as incidental findings during pathoanatomic examinations in cases of rickets, tibial dyschondroplasia (TD), and femoral head necrosis (FHN). The morphogenetic and etiopathogenetic aspects of the findings were further investigated through histopathologic, bacteriologic, and bone mineral analyses. The gross anatomy study showed that in about 10% of bones affected by rickets-specific lesions, fractures of the proximal tibiotarsus were present. A relatively low percentage (6.5%) of fractures of the same anatomic location could be attributed to TD lesions. The highest prevalence of fractures (68.5%), mainly of the proximal femur, was associated with FHN and osteomyelites. The results from the large-scale field surveys allowed us to confirm that the prevalence of spontaneous bone fractures of the legs in broiler chickens was largely associated with FHN, rickets, and TD. The poor vascularization of the grown prehypertrophic cartilage in cases of rickets and TD, as well as the osteolytic lesions in FHN, resulted in degenerative, necrobiotic processes which may entail bone fractures.

Behavioural disorders, including feather pecking and cannibalism, are a common problem in both domestic and wild birds. Damaging behaviour is polyethiological and is divided into two major groups of factors: extrinsic and intrinsic. Extrinsic factors are those that are not dependent on the species of bird-factors from outside the organism which causes injurious pecking (IP). There are three abiotic groups assigned: nutritional factors (the composition of the ration and nutritional strategies), factors of the environment (light, temperature, sound, and air), and conditions of breeding (density, size, type of system, and enrichment of the conditions of breeding). Intrinsic are the factors that depend on the species of bird – factors coming from the organism and influencing injurious pecking. Seven biotic factors are assigned: social (imitating, sexual, stereotypical and maternal behaviour), sex (male and female sex hormones), age (young and adult), stress (fear, stress and corticosterone), central-nervous (serotonin, dopamine and noradrenaline), hereditary (genotypic and phenotypic manifestation) and immunological. It is important to have an understanding of the influencing factors leading to an onset of injurious pecking in order to successfully control the behavior in game birds bred in captivity.

Behavioural disorders, including feather pecking and cannibalism, are a common problem in both domestic and wild birds. The consequences of this behaviour on welfare of birds incur serious economic losses. Pecking behaviour in birds is either normal or injurious. The type of normal pecking behaviour includes non-aggressive feather pecking – allopreening and autopreening. Aggressive feather pecking aimed at maintenance and establishment of hierarchy in the flock is not associated to feathering damage. Injurious pecking causes damage of individual feathers and of feathering as a whole. Two clinical presentations of feather pecking are known in birds. The gentle feather pecking causes minimum damage; it is further divided into normal and stereotyped with bouts; it could however evolve into severe feather pecking manifested with severe pecking, pulling and removal, even consumption of feathers of the victim, which experiences pain. Severe feather pecking results in bleeding from feather follicle, deterioration of plumage and appearance of denuded areas on victim’s body. Prolonged feather pecking leads to tissue damage and consequently, cannibalism. The nume­rous clinical presentations of the latter include pecking of the back, abdomen, neck and wings. Vent pecking and abdominal pecking incur important losses especially during egg-laying. In young birds, pulling and pecking of toes of legs is encountered. All forms of cannibalistic pecking increase morta­lity rates in birds. Transition of various pecking types from one into another could be seen, while the difference between gentle, severe feather pecking and cannibalism is not always distinct.

The aim of the present review is to summarise the information about the species diversity of wild and synanthropic birds, which have been recorded as reservoirs of influenza in Bulgaria until 2018. A total of 17 species of wild and synantropic birds were reported. They belong to 16 genera, 11 families and 10 orders of the class Aves. A list of wild and synantropic birds – potential reservoirs of influenza in Bulgaria is also presented.

Sleep disorders, such as insomnia, excessive sleepiness, alterations in NREM/REM cycles and breathing problems during sleep affect a large proportion of the population worldwide and contribute to cognitive and emotional disorders. Due to the adverse effects and risk of addiction of synthetic hypnotics, medicinal plants (valerian, passionflower, lemon balm, lavender, etc.) are established as a safe and effective alternative. Studies show that herbal extracts modulate sleep architecture and support neurological function through various pathways of interaction. Among their effects are also facilitated falling asleep and maintaining normal sleep structure, providing neuroprotection by redox regulation, anti-inflammatory and anti-amyloidogenic properties, improvement of cerebral perfusion and stimulation the drainage of waste metabolites, the accumulation of which is associated with the development of neurodegenerative diseases. This review focuses on: the endogenous processes by which herbs modulate sleep; their neuroprotective properties; their role in metabolic clearance and the synergistic effect of combined herbal formulas.