grain getting into water via birds?

[cluckin tractor]

my feeder and waterer is separated a good distance. but when i do my weekly trough clean i find a small amount of grain from the feeder in the water. about 15 wheat grains i generally find and it dosent worry me. does any one hav a explanation

 

[SoFluffy]

Happened to me with grass once, my chick got grass stuck in his mouth and while he was drinking, it fell out but with your case, probably not