Congratulations ! You'll have fun
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Mum should be giving up soon on dumb eggs once the newborns get more active. I never had to interfere with eggs, mum knows best!
A safe enclosure away from the others and rat, hawk and fox proof covered cage will be good. We improvised last year with 3 mums at the same time, so 1 had the eglu, the others were in a plastic covered (for weather protection) show cage and dog crate and I built a small run I covered with netting for each. Water has to be in shallow drinkers or as strange as it sounds - ducklings can drown. Water for mum has to have stepping stones for the babies in so they can get out - I used a flat washing up bowl so mum could dunk her head
Porridge is the best starter for both babies and mum to give them strength, then you'll also have time to find proper duckling starter crumbs, I think I found mine at petsupermarket at a good price but do shop around, prices vary widely with delivery.
Again, have fun!