It was the right thing to do, but that doesn't make it easy. I'm not sure that sending off a favourite ewe *does* get easier. It's a bit different with lambs - we are, as you say twiz, often a bit subdued after the first batch of the season goes, but with fat lambs you always knew that was their destiny. With breeding stock it's harder, no question about it.
I've decided not to tup two of mine, which was hard enough to do. The next bit's harder.