What have you done so far to help with the problem? do your ducklings have water deep enough to wash their eyes out? this is very important to keep them healthy. And to help clear this up get some Terramycin eye ointment TSC usually carries it. Is this clear liquid coming out of the eyes or is it thick like mucous? Making up a warn saline wash to rinse the eyes out is also helpful. you can find recipes online. But if this is an infection the Terramycin will help clear it up as long as it's not respiratory. Then you may need an antibiotic.