As others have said, turf tires are better on the snow and ice that R4s. My JD4100 with turfs works great on the ice with no chains (in four wheel drive). My driveway turns to ice after I leave the "pack" for a few blowings, and there is quite a bit of slope. I did buy rear tire chains and used them when I moved snow with the loader, but now that I blow the snow instead, the push force required is much less so I have not put them on for two years.
BTW, for a better price on chains, find a place that sells Peerless chain for trucks, and order the coorect size for you tractor tires (back wheels only is enough). The chains are a smaller gauge than tractor chain, cause they are expecting them to be used on a highway vehicle, but its all you need.
Chains on turfs is ultimate, since the tire is flat the chain is forced to be exposed nicely everywhere. Chains on an ag tire ( and maybe an R4) are only half exposed to the work.