My brooder is a deep plastic box. I used a kiddy pool for pekins, but when later I got a muscovy, I discovered muscovy ducklings can jump, high jump! So I bought a storage box with a lid from Walmart [cheaper than Home Depot] that even a determined muscovy cannot jump out of. However, by the time it was 4 weeks old, it was trying to jump out and so I had to fashion a chicken wire cover to stop it. I couldn't use the box lid without drilling air holes and I knew I was going to store brooder equipment and starter crumbles in it between broods and keep it in my shed.
I now have a small rescued, grey, speckled barred rock chick in there -- it has started to crow and was about to be abandoned in the woods when I stepped in and brought him home. He's small but has long legs and can jump!!! So there are advantages in getting a storage tub to brood your ducklings