Well thanks everyone.
I have learnt my lesson.
I actually have a 12 week old baby (the human kind) of my own - and my nest also includes a 6yo and an 18mnth... there is no way I would be going back for more as quick as she has! It didn't even cross my mind that she wanted the nest back for her own loopy purposes!
Thanks all for your advice.
Just for future reference - if this hen ever has more babies should I routinely remove her from them just when the last one is about to fledge?
And how long does she go into timeout for? When can I put her back in with the others?
And would removing the nest box have the same result as removing the hen?
THanks again