Puffed

Siggy, it would appear, is broody. This means you get grumbled at most determinedly if you go to the nestbox while she's there (and she'll stay there unless you do and lift her off) and will be very, very annoyed if there's another chicken already on the nestbox.

Daft beast. Especially given there's a second nesbox.

Fortunately (unlike a previous broody chook) she does break from it if, after a couple of hours of her sitting there, you lift her out and put her no the lawn with the others....