There are always predator issues with poultry of any kind (as far as I know). I would never be able to leave chickens out in open air here (and I have a completely fenced yard), even during the day, because of neighborhood animals.
My quail are in a completely enclosed cage made of metal sides and section dividers, metal mesh wire, and the bottom is coated wire, for the sake of their feet. The cage is on top of a DIY three-sided compost bin made from free pallets standing on their ends, placed under a mature tree.
When the quail arrived, I placed a heavy shade cloth across the back of the cage to prevent anything from seeing in or reaching through from the back (the cage is close to the fence). Then I placed scat mats on top of the cage to prevent anything from getting on the top or trying to reach through, or just stressing the birds by their presence. I had previously purchased the scat mats (heavy plastic with prickly, pointy protrusions on one side that would be uncomfortable for any animal to walk or stand on, and impossible to reach through). I originally got them to keep squirrels from digging up my raised beds, pots and grow bags (and cats too, but the squirrels have been far more destructive, damaging and annoying than anything else).
Last, I used another roll of the scat mat stretched across the front of the cage covering the feed trough and openings so the quail could stick their heads out to eat in peace without fear of being grabbed or decapitated while eating. I attached it with dollar store heavy spring clamps in the center and on each end so I can easily remove part or all of it to access the front of the cage to care for them and easily add food.
In winter, or when it’s forecasted to rain, I place a piece of clear, corrugated plastic sheeting (the kind that can be used on patio roofs or DIY greenhouses) over the top of the cage (but under the scat mats) to keep the birds dry and hopefully hold in heat or at least keep it less cold or windy during winter. I removed the plastic cover this summer for air flow and to try to keep them cooler. It has worked well.
I set up a trail cam to see what kind of issues might present themselves and discovered that there’s an opossum, two or three cats and some squirrels that run the fence line. The cats are the most regular. I’ve only seen the opossum about once every couple of weeks, or less, as it passes through on its way to wherever it goes. Right after the birds arrived, the opossum and a couple of cats tried to investigate and get on top of the cage, but the prickly scat mat did its job and kept them off. Since then they all seem to leave the birds alone and go their merry way back and forth across the fence rail as though it’s their freeway, without even paying attention to the birds or the cage.
If I was doing it over again, I think I might be tempted to use four T-posts and suspend the quail cage at the four corners secured to the posts instead of placing it atop a DIY wooden structure that will eventually rot and decay (although the pallets do contain the compost pile better than an open structure would).
I really appreciate having my delicious quail eggs, and find the birds enjoyable and interesting, and easy to care for. I’ve been pleasantly surprised that three or four of the hens have continued to lay so far well into Fall, even though not necessarily daily, but pretty much every other day. We are well under the 12–14 hours of daylight they say is required to get eggs, and have been for some time. That’s truly been a blessing.
I hope you’ll reconsider quail. I think they’re a fantastic option, especially for people who aren’t allowed to have chickens due to space, local regulations or HOA rules, noise restrictions, etc.