My OH was parking the old Land Rover today when he heard some squawking and stopped - he had just squashed four newly hatched Scots Grey chicks and the hen was trying to kill the Land Rover. Still 5 chicks left so now we need to try to catch them for the night. Like you, we had no idea she was incubating a clutch.
Some cream Legbars are next on my list..........

Update - all safely inside now.