For the record, you don't have a "large number of saws stolen," you have a Biblical F*cking Plague. 12 looted saws is a large number, 70 is an Exodus. And Banjo is on to something - I carry a dozen chainsaws in the bed of my pick-up, and I feel like they barely fit; whoever did this had serious hauling capacity. If you know the approximate time, area cameras might have picked something up? Look for the van sitting low on the springs, with an assh*le behind the wheel.
Otherwise, run a thick chain through the handles of all the big saws and finish the loop with a tempered steel padlock. Each foreman has one copy of a key, and the other one goes in a vault somewhere. It might not stop it entirely, but now the perps need extra tools and the time it takes to get through the mess. Even thieves don't really enjoy their work.
When you install the chains, look around; the people stealing from you are disappointed.