There is nothing wrong with an occasional treat, but occasional means maybe once or twice a week, not a little every day. Especially when they are in a transitioning stage to where they are becoming adults and laying eggs. Here more than any other time, you need to ensure they have ample amounts of EVERYTHING they need, which is what commercial feeds give them. Feed them the stuff they need, let them get into the egg laying routine, and get that sorted, THEN you can worry about treats now and then. Let the treat be the beetle or grasshopper they catch in the yard, not the sugar dud you gave them.
Aaron