What do you guys do for follow up on turkeys, assuming you didnt' see the bird go down or hear him fall over. Do you wait the customary half hour, or immediately chase after him to avoid losing the blood trail?

If I haven't seen them actually go down I will back off and wait just like I would do on a deer.  Turkeys are tough birds, and if pushed will do their best to put some ground between you.  If hit hard they do tend to hold up at the first good cover from my experience.  I've waited as much as 3-4 hours before going after them if I am unsure of the hit.  

I recall one bird that ran all the way across a big field and into the woods on the other side. I snuck out and came back hours later.  He was just inside the woods where I had last seen him, still alive, but I was able to get right up him and finish it.  I have no doubt I would have lost that bird had I chased him too soon.

Depends on the hit, cover, weather, time of day and probably a few other things.  A good hit in open field, I try to keep an eye on it and follow from afar if necessary.  If not such a good hit and heavy cover, I try to get a reading on its direction of travel, but will wait a half-hour or so before tracking if weather or light aren't a factor.  If they are, I might trail right away, or wait for the next morning.  On a good hit, most times they go down in sight. On those, I sit back in my blind, crack open a cold one or have another cup of coffee and light up a cigar and just enjoy the experience.  We only get one tag a season so no need to rush it.  

I hunt turkeys exclusively from a blind while bowhunting.  When I hit a turkey I immediately jump out of the blind and chase it if it flopping or limping off in any way.  I have chased down more than one turkey.  Break a wing bone or leg and they can't get off the ground.  I strongly suggest using a string tracker if possible, however if you need to shoot at one over 20 yards I suggest switching arrows I have found the string really drags down my arrow after 20 yards.

Thanks for the heads up fella's. Good luck to all this year. I have heard to chase after them immediately, pretty sure I can outrun a bird lol. Course I hope I put the VPA 3 blade in the right spot and won't have to worry about it. My only concern with the string tracker idea is the tensile strength of the string, I worry about it breaking/the bird running too far and breaking the string. Any reason I wouldn't be able to get some heavy duty fishing wire and rig one up myself?

fishing line*

Has to be more turkey hunter's in here I would think.....

String Tracker, do a search on here or how too section. Inside 20 yds. they work!! I do Scott, if they are flopping or hurt pretty good, get out and get on them. If they run off at the hit, than mark them and let them lay up. If ya push a bird that runs off quick, he will as Whip said lay up in the first heavy cover unless he is with other birds than may try to keep up with them. Shawn