The best defence against predators is attack and being prepared 100% of time.
I lock all my birds for night in large kennel chain link enclosure with solid roof, AND I have two good size traps effective to catch anything from small opossum to fox, set all the time I just change bait every few days before ants and other bugs consume it ( small piece of dry bread or toast with very small chunk of salami (they can not resist the aroma of salami).
I thought 2 traps is overkill until one night I cought 2 opossums one in each trap.
I am routinely catching small possums or coons before they grow larger and develop taste for my birds. There is no more large ones around anymore, I exterminated them.
Since I protected my birds that way I did not lose single bird to predators in last 3 years.
So folks if you do not want to lose your birds you need to make some effort, and attack (trap) is the best defence beside second line of protection which is proper enclosure.
But if you rely on enclosure, only, coon or fox sooner or later will find the way to get in, and you will not even know he is working on it before it is too late.