Welcome to BYC!
Hope things go better in your future flock. Can look on forums or in articles regarding predator proofing to see if any other protection is in order. Generally speaking all windows vents and runs should be covered with 19 g 1/2 inch hardware cloth and 2 ft same HWC apron around coop/run. Some additionally lay some rock on top of that around base. Best to roof coop and run. I also use Nite Guard or Predator Guard lites on coop facing woods. Sorry about your losses and illnesses!

Best wishes to you and your new flock! Sorry for your losses... Bear hugs! 
and Welcome to Backyard Chickens.
