I have the ewe after stillbirth/lamb died in a pen with no green feed at all, some hay, or preferably straw and of course water. NO concentrates - the "starvation" ration will help her to dry up quickly. For the first few days I will also check her teats twice daily and ease some milk out - put the ewe on her behind and with a squirting/squeezing action take some colostrum/milk out. I don't normally bother saving it. After a few days only once and then you will find that her teats get slacker and then she should be fine, but still no concentrates - so going out with the youngstock will be fine then. Just reduces the chance of mastitis.