That does seem excessive. I would guess that you should be closer to 30 to 40 pounds per month (although I have no idea how much turkeys eat). Is it possible that rodents or other birds are stealing feed from you? If not, you may want to consider health issues such as worms, etc. Worms will make chickens eat more.
If you are sure there are no health concerns, you may want to restrict feeding times instead of offering food all the time.
I wouldn't scatter crumbles on the ground. It wouldn't take them long to mess it up and decide not to eat it.
I'd do the opposite - keep the feed contained and get it high enuf off the ground that they have to stand on their tiptoes to eat. That way it isn't so easy for them to scatter it about. That might save you some feed but you may not have too much to save.
Maybe you should switch over to pellets. I was using crumbles before and found a lot was wasted. I find far less waste with pellets. My birds free range during the day. They also get scratch grains and bailed alfalfa garden greens etc.
Hmmm. Will have to rethink the way I deliver the food. I put it in a 5gal. bucket with holes at the bottom. About 25 lbs. fit in it at a time. This sits in a large pan with 3in. walls. So I don't think they can scatter it easily. Today was the first day I let them out of their run. (I was worried they'd fly over the fence but they were perfectly contented scratching around, eating grass and what have you. I have 1 leghorn, 1 NHR, 1 Delaware, 1 Australorp, 1 RIR. They feed at will. Then the turkey who lives with a silkie banty gets 8cups a day to share (sometimes a little more). Maybe I should switch the five ladies to so much a day in the pan instead of self feeding?
I've got seven pullets who are laying and five pullets who are still too young, and I go through about fifty pounds of feed (plus snacks and a bit of scratch) every six weeks or so. They have access to food whenever they want it. So, unless your turkey is eating a lot, it sounds like you've got some waste on your hands (or interlopers). Just my $0.02.