I have a frozen turkey that was given to me (12.25 lbs) and I was wondering how long should I brine it for?
Make sure that your Turkey is fully thawed before you brine it.
Try a overnight brine & here is a link to a brine recipe
if you are just brining 24 to 48 is normal, i don't get too locked in. If you are adding some cure to your brine I recommend about 90 to 100 hours. This allows time for the cure to fulling distribute within the bird. Shorter periods will have some of that cured flavor but it wouldn't be fully penatrated.
Everyone had their own time tables they like, but I am guessing the above will fit the bulk of all the answers. Your turkey's size wouldn't dictate a long low & slow smoking, but.... well I just did one last week about that size although a slightly enhanced butterball, I did it at 220 to and IT of 163 breast probed. It smoked for slightly over a dozen hours.I also made sure the bird was dehydrated overnite and then fan dried to form a pellicule.
Many here are advocated of hot and far and I have tryed both, I do prefer the low & slow.
BTW I did mine in apple wood and its perfect with turkey!