Well I think I will give it a go. I realise I will have to be vigilant tho. I read that the humidity required for the egg to hatch is regulated by mum duck who is likely to get into water occasionally during her ‘sitting’. Is there anything special I should provide for a sitting hen.
Firstly the hen should be set in a separate broody coop away from other hens so she can have peace and quiet. Then dust her liberally with diatomaceous earth to ensure she is louse/mite free - itchy hens wont sit for long!
Also make sure she hasn't been broody for too long before you set her. As doganjo says the incubation for ducks is longer so you don't want her to go off the boil and leave the nest. It's worth getting her into position, giving her a couple of fake eggs on for a couple of days to ensure she is still serious about sitting before giving her the eggs you intend to hatch. Place food and water somewhere nearby where she can find it when she comes off the nest for a leg stretch, poo etc. Don't worry about her not getting off every day, she doesnt need to. 3 days before eggs are due to hatch lift her gently at night and mist the eggs with a plant mister or similar to increase the humidity and then leave her to do her job. Don't be tempted to keep looking underneath her to see if they've hatched. You'll know when the babies have arrived as she will get even fiercer when you approach and you may see fragments of shell around her that she's picked out of the nest.