Ducklings with mucus??

[LaynaDon95]

I'm watching some ducklings for a friend and I've noticed that there is mucus hanging out of their bills sometimes when they drink. Is this normal?

 

[jessiduck]

Sometimes this can occur when the ducks are trying to clear out their nostrils. Honestly, I would monitor this condition and if you see that it keeps occurring bring them to a vet. It could be a sinus or respiratory infection!