Missing part of skull?

[DukesDucks]

One of a group of 18 barnyard mix chicks that hatched yesterday has an issue. When first hatched this red lump on top of its head was significantly larger. This pictures is at about 12 hours old. Now, at a day old the lump is smaller and soft. The chick is active, eating, drinking and vocal. I watched the group and none of the others are picking on it.
I would appreciate any suggestions as to what this actually is, and prognosis for its future.

 

[MysteryChicken]

One of a group of 18 barnyard mix chicks that hatched yesterday has an issue. When first hatched this red lump on top of its head was significantly larger. This pictures is at about 12 hours old. Now, at a day old the lump is smaller and soft. The chick is active, eating, drinking and vocal. I watched the group and none of the others are picking on it.
I would appreciate any suggestions as to what this actually is, and prognosis for its future.
View attachment 4081317

Exposed Brain. This is often a cull.