Is your run made from heavy duty 1/2" hardware cloth with a deep buried skirt all around the edges? No gaps anywhere? Full roof/cover?
If it's just regular poultry netting then it is NOT predator proof. Raccoons will bite through it, weasels can zip through it, rats, possums, oh-my-gosh...
Day-time predators are easier to foil, but those night guys will spend the time to do real damage to get to the prize. A nice wooden door is what makes me sleep well at night; the routine of tucking them in also gives me an opportunity to check their well-being, too, as we do role-call. It's funny because if I say their names, the correct chicken will often answer.
It's 3 minutes out of my life to lock them in, and I think it's important.