Thanks for all the advice, dear TAS people!
So I'll leave her a few days more, and keep my fingers crossed that a couple more may hatch.
She looks happy enough, but I'm a bit worried that the hatched chick is very lively and could hop over the nestbox ledge and then won't be able to go back - there is no drop in level, but there is a ledge. It did hop into the adjacent nestbox earlier today, then stood there cheeping
very loudly... I heard it 20 metres away... but mum just sat on the eggs...
As she's still sitting tight, she's not really taking the chick to the feeder... should I be worried? I don't think the egg yolk will sustain the chick beyond today if it hatched yesterday?
I've been sprinkling some chick crumb in front of them and both mum and chick have been picking at it, but it gets soon lost in the straw. There is food and water in front of the hen, but obviously too far to reach for the chick - unless it hops over the ledge again...
Questions questions... every 'first time' on the smallholding is equally amazing and nerve-racking... wouldn't want it any other way