The study of vertebrate evolution relies heavily on the identification of homologs in different lineages. However, the use of different definitions of homology has led to controversies regarding the identity of certain homologs, and consequently differing proposed evolutionary histories. One such controversy is the identity of the avian frontal bone. Morphologically the bone has been defined as a frontal based on its shape and position in the avian skull. Developmentally, however, it is proposed to be a fused frontoparietal because it develops from two ossification centres with embryonic origins similar to the frontal and parietal of outgroup taxa. To help resolve this controversy we examined the comparative histology of the region between the frontal bone’s two ossification centres, plus five known sutures in the developing Gallus domesticus skull. We determined that given the absence of the middle vascular layer, which commonly occurs within developing sutures, the gap between the frontal bone’s ossification centres is not a suture, implying that the frontal bone is not likely to be a fused frontoparietal. Our result is in congruence with recent comparative anatomical analyses of the skull roof in Archosauria that reject the frontoparietal hypothesis. Moreover, it represents the first histological examination of chicken skull sutures carried out to date.