Indeed, lambing time is great, provided all goes well, otherwise it can be dreadful. Buy hey, its not happened yet!!
I'm bringing my ewes in this weekend. They are due around the same time as yours I think - 15th onwards. But mine have to be transported from my rented fields, 3 miles away, so I'll be bringing them home in good time and they'll be out on the small paddock here where they will be allowed in and out of the (new and posh!!) shed during the day if the weather's fine. I will only shut them in the shed if the weather turns (which I think it is due to do from the 12th according to the Met Office forecast) and at night, every night. I usually keep ewe and lamb(s) in pens for two or three days, depending on progress, and then, if its reasonable weather, allow them out in the daytime.
I will be watching 'Lambing Live' on BBC 2 from this Sunday to see how the other half live - the ones with vast amounts of sheep to contend with. Cheers.