Effects of Genetic and Production Type on Egg Cholesterol and the Yolk–Albumen Ratio in Slovenian Chicken Genotypes Under Standardised Conditions

Eggs from ten Slovenian chicken genotypes-four layer-type purebreds, three meat-type purebreds, and three commercial F₁ crossbreds-were analysed at 50 weeks of age (n = 118). All hens were reared indoors in identical floor-barn systems and fed the same complete layer diet, with feed intake restricted only in meat-type hens. Cholesterol was determined spectrophotometrically, and results included cholesterol per yolk dry matter and fresh yolk, per whole egg and egg content, total cholesterol per egg, and the yolk-to-albumen ratio. Production type significantly affected all traits (<i>p</i> < 0.0001): meat-type hens had the highest cholesterol concentrations and totals, layer-type purebreds were intermediate, and crossbreds the lowest. The yolk-to-albumen ratio showed the same gradient (≈0.44 in crossbreds, ≈0.46 in layer purebreds, ≈0.50 in meat types; <i>p</i> = 0.004), indicating that a larger yolk fraction contributes to higher total cholesterol. Reciprocal crossbreds did not differ in cholesterol levels (<i>p</i> > 0.05), suggesting negligible maternal or sex-linked effects. Under standardised conditions, genotype and production orientation were the main determinants of egg cholesterol and yolk proportion. These results provide reference values for Slovenian breeding and conservation populations and confirm exploitable genetic variability for future selection aimed at improving egg composition.