That is a very astute observation. Typically when I see narrow headed hatchlings, they are typically the ones that have problems with the yolk in one way or another. I attribute it to them having problems absorbing prior to slitting the egg, and this is why their heads are smaller. You may have to get a closer look at the umbilicus and yolk if it is not out in the next 24 hours. There may some type of problem. If so, all hope is not lost. I have plenty of babies that didn't absorb any yolk, and lead normal lives with a little TLC in the beginning.
Good luck,