Once or twice with raccoons means there's always a possibility they'll rear their ugly heads. If you're using the same method on your chickens its only a matter of time. Some get lucky. Some don't. The important thing to remember is quail can fit through tiny tiny holes you didn't know existed.
They tend to stay away from my yard because of my dog. The last time one just put a paw in our yard my dog was right on him. He climbed up a tree before she got him but I think he got the message.