The objective of the study was to evaluate the effect of breed and thermal treatment methods on the meat quality of organically reared hens. The study material consisted of single breast muscles of the Green-legged partridge hens (n = 20) and Rosa 1 hybrids (n = 20). Evaluated were the quality of raw breast muscles and the quality of those that were thermally treated, i.e. cooked and roasted. The quality evaluation of raw breast meat included the following: acidity (pH15, pH24), colour, shear force, water holding capacity, dip loss, and chemical composition. The evaluation of the thermally treated breast meat included: colour, shear force, chemical composition, thermal losses, and sensory characteristics. The evaluation results of the raw, cooked, and roasted breast muscle meat derived from the organically reared hens after the period of using them as layers indicate that the meat derived from the Green-legged partridge hens has a better culinary suitability in comparison to the meat of the Rosa 1 hybrids. Compared to the raw breast meat of Rosa 1 hybrids, the breast muscle meat of the Green-legged partridge breed of hens was characterized by a darker colour, lower fat content, and lower dip loss; after the thermal treatment, it was characterized by a lower cooking loss, higher protein content, lower fat content, and better brittleness; also, its taste was better. Compared to roasting, cooking turned out to be more beneficial in terms of getting better tenderness and taste desirability of meat derived from hens after the accomplished period of using them as layers; this fact could be of practical importance for consumers.