Differential expression of gga-miR-142-3p microRNA of haemopoeitic origin during immune organ development and functional stages in chicken embryos opens the new avenue towards understanding its pivotal role during embryonic developmental stages. To decipher the role of gga-miR-142-3p, in-ovo knockdown was carried out with locked nucleic acid (LNA) modifi ed antimiR- gga-miR-142-3p via, intravenous route at developmental and functional stages of these immune organ and visceral organs. Bioinformatic analysis revealed that predicted gene TGFβ2 have conserved binding sites at 3’UTR for gga-miR-142-3p which is involved in immune response and signal transduction during the embryonic developmental stage in the chicken embryos. TGFβ2 was evaluated as validate targets of gga-miR-142-3p by employing qPCR SYBR green based technology which was evidenced by aberrant expression of targeted gene, which could alter the postnatal development and functions of these immune organs and may lead to immune compromised chickens.