I agree Sally that they
really don't need any feed at all beyond grass. If you will be keeping your males then you don't need them to 'fatten' - in fact you don't
want them to fatten. Same with the ewes - you want them to be in good condition by tupping time but not overfat which they will become with added feed on top of rich summer grass.
For bringing them in, we use Carr's Champion tup, but only enough to make a bucket rattle ie a tiny hand-not-full, and definitely not every day. It's what we feed the whole flock in winter as the ewes don't need a higher protein content than this coarse mix supplies, being primitives, and they don't need much even then. The tups and non-breeding ewes only get concentrates when there's snow lying - they get ad lib hay and branches, and whatever grass there is left.
Negative reinforcement works by not always giving the reward and is as successful as positive reinforcement, so don't worry that they will forget the bucket rattle - sheep don't forget
I can't remember what breed your sheep are, but I'm surprised they still come for the dry feed - ours just aren't interested.