I love the puppy pads- makes cleaup fast and easy.
When they get a little older they tend to scratch at them and dig at them, but as little chicks they're fantastic.
I did use mine on the ducklings, too. They worked great, had to change them a lot, so it could get expensive, but at Walmart they are about 13 bucks for a 50 count bag, so not too outrageous. I ended up switching the ducklings to horse bedding pellets (Equine Fresh) and putting a puppy pad in one section of the brooder pen for them to sleep on (to clean the powdery bedding off them). Using just one for them to sleep on helped with total usage/cost.
Puppy pads can be a bit expensive where I live. I found bed liner sheets near the incontinence pads and supplies in the health aisle at Walmart. There are a dozen or so in a pack and they are only a few bucks. Same thing as puppy pads, one absorbant side and one plastic side.