The proper age to select the Nigerian heavy local chicken ecotype (NHLCE) for fast body weight improvement has not been established, and efforts by Nigerian breeders have been on to establish an average age to select the birds for quick genetic improvement on productive traits. The study was conducted to evaluate the body weights and heritability estimates of the Nigerian Heavy Local Chicken Ecotype reared in Nsukka. A total of 350 and 345 day-old chicks for generations (G) 7 and G8, respectively, were used for the study. Generation G7 chicks were produced from the existing generation G6 parent stock, while G8 chicks were generated from G7 parents, in the Teaching and Research Farm, Department of Animal Science, University of Nigeria, Nsukka. Thirty (30) mature cocks and 90 mature laying hens were randomly chosen from the G6 parent stock, and divided into six breeding groups at mating ratio of 1 male: 3 females, to produce the G7 chicks. Fertile eggs were collected, incubated and hatched according to breeding groups to produce the chicks for the study. Similar protocol was applied to generate the chicks for G8 study. Feed and water were provided to the birds ad libitum. Data on body weight were collected at 4 week intervals. The study lasted for 24 weeks. The results showed varying body weight performances across the breeding groups and across the generations. Breeding group 1 had the highest body weight at hatch (40.38±0.58g), whereas, breeding group 3 in G8 was highest at 24th week of age (1846.15±32.93g). On the generation performance, the results showed that from hatch to 24 weeks of age, body weights (38.33±0.24g to 1605.67±18.13g) of generation G8 birds were significantly (p<0.05) higher than those (37.45±0.26g to 1352.11±17.39g) of generation G7 birds. The heritability estimate ranged from 0.12±0.19 to 0.84±0.88 and 0.12±0.35 to 0.49±0.74, in generations G7 and G8, respectively. The heritability estimates were highest at week 4 of age for both generations G7 and G8 birds. It was therefore concluded that selection for body weight in the Nigerian heavy local chicken ecotype is better carried out at 4 weeks of age.