The prolactin (PRL) gene influences the commencement of incubation and brooding behavior and egg production, particularly in native birds. In this study, the first experiment was performed to screen the PRL candidate gene for single nucleotide polymorphisms (SNPs) in four different morphological types of Nigerian chicken, and to evaluate their molecular evolutionary changes. To achieve this first objective, a 130-base pair (bp) fragment of PRL was sequenced in 40 different Nigerian chicken types namely, 13 Heavy Ecotype (HE) cocks and hens, 13 Light ecotype (LE) cocks and hens, 7 Frizzled Feathered (FF) cocks and 7 Naked Neck (NN) cocks. In the second experiment which aimed to associate the SNPs of the LE PRL with egg traits, 13 LE cocks and hens from the indigenous flock were screened. Three SNPs were identified in the Nigerian chicken ecotypes (A=Adenine, G=Guanine, C=Cytosine, and T=Thymine), namely G > T, T > C and A > C having allelic frequencies of 7 in NN, 10 in HE and 4 in both FF and LE chickens. Comparison of the chicken PRL (cPRL) sequence gave 98% homology with White Leghorn (Accession No. AB013783.3). The Tajima "D" test of neutral molecular evolutionary rate was 2.79, suggesting balancing selection in the cPRL. In associating the SNPs with egg traits of LE, three SNPs were identified in the LE chickens namely G > T, T > C and A > C having allelic frequencies of 4, 3 and 4, respectively. The cPRL genomic sequence consisted of 154 bp long. The T > C polymorphism showed significant (P<0.05) negative association with egg number and egg size. The findings in the second experiment showed that the homozygous TT genotypes showed better egg weight and egg number performances than the TC individuals.