In this study, the effects of using soy oil (SO), poultry fat (PF) and tallow (T) in feed at fixed energy : protein ratio on broiler performance were evaluated. When PF and T were used instead of SO, especially in grower feed, the field performance improved except for mortality. This situation was not seen in slaughter performance except for a few cases. At the end of the study, it was seen that if certain ratios are not exceeded, the use of PF and T instead of SO may be economic alternatives.

The aim of this study was to evaluate the time to sexual maturity and the quality of the initial eggs of Japanese quail affected by in ovo injection of plants extracts: ginger, garlic, oregano and cinnamon. The in ovo use of medicinal herbs may considerably modify both the time of sexual maturity and the quality of the initial eggs of Japanese quail.

The effects of hypoxia at increased altitude levels on the cardio-respiratory development of broiler embryos are distinct in comparison with those at sea level. The study aim was to investigate the effects of high incubation temperature and oxygen supplementation during hypoxic high altitude at different embryonic stages of developmental and physiological traits of embryos and hatching performance of embryonated hatching eggs in broilers. A total of 1280 eggs obtained from broilers.

This research was conducted to establish whether flooring systems, i.e., plastic, could be good alternatives to deep litter. What we have found is that in terms of some animal welfare parameters, such as footpad dermatitis and hock joint dermatitis, slatted floor housing can be a good alternative. However, as the birds get heavier, some other welfare problems occur, such as lesions on the breast and shoulder.

This paper shows the impact of the rearing system used for laying hens on their productivity and egg quality. Newly created laying hen hybrids dedicated to organic or pro-ecological farming were used. The results showed different reactions of two types of hens to extensive and intensive rearing systems. A significant positive impact of the extensive rearing system (access to open runs, natural length of daylight, farming fodders) on birds and their productivity was found.

Fatty acids and nutritional indices in meat were studied in La Belle and White Plymouth Rock birds at 9 and 18 weeks of age. The study is the first in Bulgaria to assess the potential of lines of the national gene pool to produce slow-growing chickens with a high quality of meat in regard to its lipid profile, affected by line and age of the birds. Total monounsaturated fatty acids decreased, but polyunsaturated acids increased with age, leading to beneficial changes in the nutritional indices.

In this study, broilers were raised in standard pens versus in pens equipped with perches to study effects of perching on growth performance, carcass characteristics and footpad lesion (FPL) in broiler chickens. Perch availability did not change growth performance, carcass yield and proportions of carcass parts, but affected certain meat properties and had a positive effect on FPL. Potential effects of perch use with respect to health, meat quality and performance should be further investigated.