I know Coturnix appreciate low cover like grasses and shrubs. I've also found taller cover (e.g. chunk of hollow log, big flake of bark off a dead tree, well-placed cardboard boxes even) help break up line of sight during the hen's yearly hormonal chase-chase, and give them ways to feel safe from neighborhood predators and each other.
Here's my setup for Coturnix:
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The green netting is separating my broody from everyone else, more for their sake than hers.
And here's what I'm planting soon to replace those yellowed muhly I forgot to water...
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No matter what you build, as long as you're giving them "furniture" that provides low cover and breaks up line of sight without taking up too much floorspace, you're going to have more active and naturally-behaving quail.