HOX genes are more about body plans, so like, if the chick had legs where it's eyes would be, Id lean toward HOX. This chick looks like it has a non-functional set of legs stuck on the back of it, which would make me lean toward a conjoined embryo.
You can kind of see the wings on the front chick. Also the 2nd pair are on backward, like a butt-to-butt fusion. Im not saying anything definitive here because the pictures arent great, and I havent worked with HOX for like....17 years. So take this with a grain of salt.
-1
u/Cat_Peach_Pits 29d ago
Far more likely to be conjoined than a HOX error.