Mine know where their food is at night. I guess it is more a daily routine they have gotten used to. Mine live for routines, because that is something in their comfort zone. They now get food twice per day. In the morning I fill a bowl up for outside time, which is usually empty in the early afternoon. From there they forage until it gets dark and they get hungry again. That's when they have their night food ready in the duck house. I see them going straight for it when they go into the duck house. That bowl is usually empty in the morning the the cycle starts over.