I have had Quail in with my Silver & Chinese Ring-Necked Pheasants in the past, & they were fine.
If the pheasant are in the pen first, I have had to acclimate them first by placing the quail in a cage, & then placing the cage w/quail inside the pen for 2-3 days.
First day, I open the door...
I am up in the northeast, & the cold weather is very hard for them. Lack of as much food & cover/shelter. Where they get in trouble is when they rely on birdfeeders and range feeders. Its alot easier than lookin for natural food. Predators learn about the feeding spots & use them to their advantage.