If you have a lot of hens in a coop, there's no real sign unless you see her laying in a nesting box...which is unlikely. If you really need to know about a particular hen, the thing I'd suggest is isolate her for a few days. Dog crates are really good for this. Make sure she's comfortable, with food and water and a safe nesting box in there...as chickens stop laying when they're stressed...so you want her to make a nice little house in there for a few days.
Is there a way to tell if a hen is laying?
If you have a lot of hens in a coop, there's no real sign unless you see her laying in a nesting box...which is unlikely. If you really need to know about a particular hen, the thing I'd suggest is isolate her for a few days. Dog crates are really good for this. Make sure she's comfortable, with food and water and a safe nesting box in there...as chickens stop laying when they're stressed...so you want her to make a nice little house in there for a few days.