Sure they used a tractor??? Around here the junk guys are just stopping and cutting them up where it is setting an taking off. Read in one of the farm magazines where someone out west lost a fairly new field cultivator that way. Showed a picture of where the grass was brunt from them cutting it up.
If it looks like scrap iron you need to have it nailed down or some body will steal it today.
Good friend collects old single cylinder hit and mis engines. His shop always has a few setting out front waiting for him to fix or repair. Some one stole all of the ones that where outside a few weeks ago. My friend checked the scrap yards around and found where they had been hauled. Got into a big fight with the scrap yard. Even called the law. Did him zero good. He had to have a exact list of the engines and receipts where he bought them. Some of these engines may have been boughten 20-30 years ago. Also a lot of them came from flea markets. Every got a receipt at a flea market??? Long and short the county sheriff just did not want the bother of fooling with something he thought was of low value. Friend had to buy them back for scrap price.
Some one on here was talking about how some one broke into his sheds and stole a bunch of Ford motors here a while back.