A lot will be down to the age of the ewes as an older ewe feeding twin lambs will be in a much poorer condition than a 2 year old ewe feeding twins. It takes a lot out of a ewe to feed her lambs and herself before lambing and then the ewe has to sustain those lambs for months after birth. A very good ewe will put most of her energy in to keeping those lambs in tip top condition and the condition can therefore fall away from the ewe herself.
If you have put out hay and the animals are not interested in it, then they are not hungry. You sould as if you are doing everything with putting out a lick and offering ad lib hay, so I would look towards weaning the ram lambs off about 16 weeks and then you should see an increase in body condition to the ewes. Give them plenty of time to get in a good fit condition before putting the ram in again next Autumn.