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And asks the barman if they have peanuts. The barman answers no (he doesn't want to serve ducks I think). The day after the ducks come back, same question, same answer.

The day after the ducks enter "hey barman do you have peanuts ?"
The barman "no we don't have, look don't come back everyday asking for that, next time I'll nail your face on the desks so fuck off"

Next day the ducks enters "hey barman do you have nails ?"
barman "nope don't have any..."
duck : "ok barman do you have peanuts ?"