Our 4 chicks will be 4wks old THIS weekend. We have our coup set up and ready and it's completely covered. At the rate they're growing, they will outgrow the brooder they're in now before they're 6wks of age. What's the earliest I can move them into the coup? Can I move them within the next week or do I need to find something larger to put them in until they're 6wks of age?