Hi why did one of my chicks disappear??

[Tallisdibrani]

My chicken came broody and had two chicks which were about a week old they were doing fine normally I check every night /day to make sure they got enough water ect but didn’t not yesterday day before and than did check yesterday and the chick was gone - I looked around everywhere in their stable and couldn’t find the chick and didn’t see a lot of feathers in one area or anywhere really so does anyone have an idea of what might’ve happened? I’ve moved the hen and now her only chick to the barn in a safe stable (have horses)

 

[Tallisdibrani]

Also when the hen was laying on the hatching eggs her comb went grey and then when they hatched she had her red comb coming through again but now it’s grey/white again. Would this have anything to do with it ?