I have some ewes just being served now as I deliberately didn't put the tup in til mid December. He will stay till the end of January. Hopefully none of the adults will miss

but if they do it's no disaster for me
Bung em in and enjoy a (hopefully) warm June lambing
One word of caution though, keep an eye on lambs born in the warm months, sometimes if the membranes don't get licked away quickly enough or the ewe is preoccupied with a second lamb they can get fly eggs laid on them very quickly