“…In poultry, several candidate genes have been identified showing polymorphism associated with egg production. The prolactin (PRL) gene has important functions in birds, specifically in egg production in chicken (Li et al, 2009;Rowshan et al, 2012;Wilkanowska et al, 2014;Brijendra et al, 2018;Roy et al, 2020;Manoharan et al, 2021;Rohmah et al, 2022), duck (Wang et al, 2011;Chuekwon and Boonlum, 2017;Ghanem et al, 2017;Astuti, 2019;Sabry et al, 2020;Nguyen et al, 2023), goose (Ma et al, 2015;Tang et al, 2021), and quail (Yousefi et al, 2012;Lotfi et al, 2013;Eichie et al, 2016). In chicken, the size of the prolactin gene is 9.536 bp and comprises three parts as (i) three promoters (Kansaku, 2000), (ii) five exons (Ohkubo et al, 1998;Miao et al, 1999;Cui et al, 2004), and (iii) four introns (Dhara and Soller, 1999;Au and Leung, 2002).…”