There's no definitive answer to this question. If you leave the tup in all year round you will not know when your ewes will lamb. Hebs are generally seasonal breeders but there are enough little unseasonal surprises around to disprove that rule. Some tups are fine running with the ewes when they are lambing but some are not - a ewe in labour gives off strange messages to a male, who may butt her and even kill the new lambs - or he might not. The simplest answer is to keep the tup in with the surplus male lambs which will be going for meat. We wean our lambs in late August then run them on for a full year, sending them off in early August. We have several tups so even for those couple of weeks (while the grass recovers) they are not alone, but you could do it so the shearlings went off one day and the lambs were weaned the next, or even the same day. This system requires a minimum of 3 paddocks, so you can also wean the ewe lambs but keep them separate from the tups and from their brothers.