You can start giving treats as soon as they fit down their little bills easily. Just add the grit right into their feed, a pinch in each bowl stirred in will do it. They especially like frozen peas or mixed veggies tossed in their water to go diving for. If you use the mixed veggies just watch the green beans as sometimes they are a bit big & may need chopped up for small ducklings.DUCK questions!!! Went can I start to treat them and what kinda grit at their age... ancona from New years eve????????