Diversity in Population Size and Production Parameters of Selected Varieties of Plymouth Rock Chicken Breed

Objective of the research was to compare population size, eggs and meat production of the locally adapted chicken breed – Plymouth Rock of different varieties (white, barred and buff) in Slovakia reared in extensive system. From the view of population size in conditions of Slovak Republic, most numerous of Plymouth Rock variety is white (average effective population size 118.96), while the lowest numerous we recorded for buff variety (21.62). The highest eggs and meat production we noted in case of White Plymouth. For this reason, this variety of Plymouth Rock was used in hybridisation for development of modern hybrid combination for production of broiler chickens.