Our birds are 12, 14, and 20 weeks. The 20 week old ones are some tiny WCB Polish birds. I have them all on Purina's Start and Grow. When should I move up to the laying feed. Our feed store says now is the time. However, everything I've read says not until they begin to lay. How do I feed these different ages and give them what they need nutritionally? They get all kinds of other food - my garden is huge and they've taken over, they steal bird food from the feeders, meal worm treats, vegie scraps from the kitchen, scrambled eggs once in a while, etc.... Thanks!