I'd always cake hoggs a little, but only a little if they are carrying a single. More if they are carrying twins, of course.
Generally otherwise a single-bearer should be fine on good hay plus minerals.
Twin-bearers more likely to need some hard feed unless some or all of the following are true:
. tup same breed or small / easy-lambing breed
. ewe breed is milky and thrifty
. forage is good quality and plentiful
. no other stresses - good ground, not too wet a winter, etc
BH never caked Texel ewes at all for years, being concerned about over-sized lambs getting stuck, but the ewes didn't milk very well for twins without some hard feed in the last month at least. We're on upland Cumbrian ground, of course, so by now there's little in the grass and even our hay and silage won't be very high feed value compared to a lowland farm / more southerly farm.
If not caking then I would certainly give minerals throughout, and sugar / treacle in the last 6 weeks too.