Three days is about as long as you want to brine chickens, turkeys I’ve had them in brine for up to 5 days with good results. When I want to flavor turkey alittle more that’s what I do, I cut back on the salt though alittle bit if brining that long. I think it helps the other flavors come through better.

also with turkeys you want to find unbasted fresh turkeys, it’s tough to get a consistently good brine on a basted turkey.