Hello so first question, I went out & purchased some grit today for my ducklings. I was wondering how much do i need to feed per meal? Today I just sprinkled some of it over their grain? I have 5 ducklings probably about a week old. (I purchased the ducklings yesterday). Second question- I would reaallyy like to go non-gmo/or organic for their feed. Any suggestions? Right now they are being fed Manna's Game/Show feed (they gave me it at rural king the day I picked up the babies). Thanks!