1 and half week old ducklings whistling when breathing

[alva1832]

This has been going on for about 2 - 3 days. Some information on how I'm keeping them; they have water deep enough to dunk their heads in, using specialised duckling feed, it does sometimes get damp in their brooder but i cant really do much about that since its like 90% humidity at night and I replace the wet parts of the bedding in the morning. They look perfectly normal otherwise (eating, drinking) just when resting two of them start whistling (actually as I write this its more like if you have a blocked nose and air is trying to get out) i do notice them breathing abit faster too. I'll post a picture of my set-up.