Anyone know what this is on baby chick’s belly?

[Tk5806]

See photo for a 4 day old chick’s belly that has a gap between her feathers where something hard is protruding in a line down her stomach. Can anyone tell me what this is and if it is normal or not?

 

[Blue Raptor]

See photo for a 4 day old chick’s belly that has a gap between her feathers where something hard is protruding in a line down her stomach. Can anyone tell me what this is and if it is normal or not?

Probably the keel bone.