we raised chicks and ducks at the same time last year and I can confidently say we could/would NEVER put them in the same brooder. The ducklings do grow up so much faster than the chicks and will trample them without hesitation. And then there's the fact that they are soooo ridiculously messy. And they LOVE it! They'd poop all over the chicks and their food and water. And they stink. And are messy. And have I mentioned that they are messy? LOL.Can chicks and ducklings be in the same brooder?
Having said that, we love out ducks...but if they weren't my daughter's and her responsibility, I wouldn't have them at all.