초록
160 day-old chicks of Rhode Island Red, White Leghorn and their crossbred with Naked neck chicken were reared upto 23 weeks of age at Bangladesh Agricultural University Poultry Farm in order to study the economic traits of birds. RIR had highest body weight gain (1494.39 g), followed by White Leghorn (1392.57 g), $RIR{\times}NN$ (1268.9 g) and White Leghorn ${\times}$ NN (1266.73 g). RIR showed significant difference (p < 0.05) to other groups of birds in body weight gain but difference were insignificant in between other birds. RIR showed better feed conversion ratio (4.72:1) but difference were insignificant (p > 0.05), however, $RIR{\times}NN$ exceled White Leghorn ${\times}$ NN in feed efficiency. $RIR{\times}NN$ had highest livability (90%) while White Leghorn had lowest (85%). Earlier sexual maturity was observed in White Leghorn (163 days) than RIR (168 days) but cross breds were similar in age at sexual maturity RIR were heaviest (1538.89 g) at age at sexual maturity, on the other hand $RIR{\times}NN$ were heavier (1315.39 g) than $WL{\times}NN$ (1306.77 g) at sexual maturity.