NTRK3 and Infertility: For WL chickens, the copy number deletion of CSMD1 and NTRK3 may be involved in the outstanding reproduction traits, because NTRK3 and CSMD1 have been reported to play crucial roles in follicle development, ovarian quality, and infertility in human and chicken (Lachman et al., 2007; Nilsson et al., 2009; Lee et al., 2019).