Good work predator proofing the run! Check the coop itself for predator proofing like locking mechanisms (raccoons are able to open many types), and wire mesh which often is only held with staples, easily punched out by anything stronger than a mouse.
Your chicks won't need heat once they are outside even in winter. However your chicks are currently too young for cold. Reduce the temperature in their brooder slowly to acclimate them. I forget how much or often. Let's ask someone like @aart . They do need their feathers to grow out, not just the wings.
Your chicks won't need heat once they are outside even in winter. However your chicks are currently too young for cold. Reduce the temperature in their brooder slowly to acclimate them. I forget how much or often. Let's ask someone like @aart . They do need their feathers to grow out, not just the wings.