OF course you can, It sounds like about 70% of the readers on the waterfowl area firmly believe that medicated feed is still toxic to ducks. If they can do it so can you! I just believe that is better not to take the risk. Things change, If you want to do what your grandma did, go for it! Seems to be the rage today, organic farming, do not ship any of your production out of your area, buy local, etc. They call it sustainable farming, I call it subsistence farming. I grew up on a family subsistence farm, If we didnt grow it we didnt eat it and we had one cash crop for farm income. My father farmed the place during WWII with a team of horses even though he had a John Deere and a Fordson up on blocks in the barn. Oil products were rationed and we could make more selling the ration stamps than using it in the tractors. No thanks I dont want to go back to the good old days nor do most people who lived through them because we remember how good they were not. The butter and egg money bought my clothing. the birds that "the fox ate" ended up on the table of people who had money but no 'meat ration stamps'. Sorry got carried away. Sure you can risk your peeps by using unmedicated starter.
Your money, your birds, your choice.