Do you think they require a vit and mineral lick to ensure they are getting all the nutrients they need.
Not sure (sorry, can't remember) where you are, wellies, but pretty much the whole of the UK is copper-deficient and a lot of it is also cobalt & selenium deficient too.
Pregnant ewes of some breeds need copper; the effects of deficiency being a condition in the lambs called 'swayback' as affected lambs may be unsteady on their back legs. Some breeds do not need (and could be poisoned by) extra copper, such as Texels. I don't know about Rylands, so hopefully someone who knows the breed can tell you whether they should get copper.
If you don't usually give minerals then I would certainly give a mineral drench either before or after tupping and again a couple of months before lambing. The thing with drenches is you can be sure every ewe is getting a dose, whereas they don't all necessarily lick the blocks and get as much.
If you check about the copper and buy a mineral block accordingly it won't hurt to have a block out anyway. And some people swear by rock salt being available to all stock at all times - it certainly won't hurt.
BTW, in case you weren't aware, you will need to vaccinate the ewes a few weeks before lambing to pass immunity to the clostridial diseases on to the newborn lambs. Heptavac-P or Covexin-8 are the usual choices. If your ewes are not already on one of these systems you should either give them an initial course now (two jabs, 4-6 weeks apart) and another a few weeks before lambing, or risk leaving their primary shot until 6 weeks before lambing with the booster 2 weeks before.