I used to raise ducklings in a cardboard box in the shower at our old place as they were safe from the cats there. OH was never too impressed though
![Sad :(](https://www.accidentalsmallholder.net/forum/Smileys/default/sad.gif)
Now they start off in an old 6'x4' shed which is lined with chicken wire inside to stop rats getting in and I can reach an extension lead there for a heat lamp. Once feathers arrive they usually move on in to a rabbit hutch for a bit until big enough and water-proof enough to move into a coop and run.
One thing I used to use are those big plastic storage boxes you can get from B&Q or similar. They are easy to clean out and with a bit of chicken mesh spread over the top, nothing can escape. Stick a desk lamp pointing in to it with a 100W light bulb and you've got a very cheap brooder box!