[Penny Finn]

Not sure if anyone can enlighten me.  I have two remaining chickens.  One lays regularly, sits on the nest box then comes out into the run and crows proudly.  The other one immediately goes and sits on the nest and egg!  I don't think she is broody because she doesn't stay long, just long enough to make me think she has laid - if I didn't know better that is!
Is this very strange or not?
Grateful for an explanation if anyone has one

[kegs]

I'd say it's normal because one of mine does it too (she lays soft shelled eggs and doesn't want the other girls to know so she sits on one of theirs for half an hour and then comes out proudly making a racket as if it were all her own work!!). 

[Penny Finn]

Do you think she will eventually get back to laying normally then?

[kegs]

How old is she, what breed and when was the last time she laid?

[Penny Finn]

She is about a year old and a black rock.  I don't think she has laid an egg for about 5 months!