As people are no doubt aware by now - I lamb mostly woolshedders of one sort or another (and some Lleyns) outdoors with minimal interference. I do vaccinate, I mostly use Bravoxin though. I have fed a bit of hay /licks this year and I have got through about 5 bags of nuts per 200 sheep in total, but that was really only because the grass hadn't started growing - this year is the exception, I normally buy 1 sack of nuts per year, in case anyone needs penning as they are ill etc. The key to having sheep that 'do' off grass is to give them plenty of...er...grass.
I stock no more than 1.5/head/ac in winter and just over double that in summer, on unimproved chalk downland (most of which hasn't seen a plough in living memory). The right breeds are important. I would be terrified of lambing mules on this system, for example, because it is a major hassle of you do have to interfere at lambing. On the plus side, you hardly ever do have to interfere, so in reality you spend much less time pulling lambs. A good, sensible culling policy helps to minimise any stressed animals on your system. Try and buy from people who have a similar outlook on culling. I worm only when FECs show worms are present and 2012 aside ( I wormed 2-3 times last year, depending on which mob they were in), I can go from one year to the next not worming ewes at all.
Ignore most of the literature when it comes to condition scoring. Outdoor lambing ewes should be fit and not fat. They should be at no more than cs 2.5 (cs 2 is fine) when they go to the ram and this will drop during pregnancy. Nature should see to it that they regain condition after lambing as your lambing will coincide with the grass properly kicking in. Down here, I usually aim to start on April fools day, but I held back this year.
Ram choice is important - look for good maternal ebvs if you are selecting replacements, and even if you aren't it should come from an outdoor lambing flock and should not have needed pulling himself.
When it comes to lambing itself - try not to get involved. I know this is hard. Time is one of the most important things you can give a ewe. Binoculars are a very useful tool. To aid me I spray number every ewe a while before lambing so I can see who is who. I try not to disturb the ewes much at all during lambing, observing from a distance and avoiding stirring them up. Definitley do not check on them when it is dark - you will do more harm than good spooking them with a torch at night time. Because I am performance recording, I catch, tag and mark lambs at birth - but if you aren't there is really no need to touch them until they are a month old. Iodining navels is much less important outside, like anything you have to asses risk based on the prevailing conditions. If it is very warm and muggy, Id be more bothered about iodining navels than if it was dry and windy. Again; if you are lambing in the pouring rain (see: April 2012) and everyone is hunkered down with their mothers, I would personally leave them be and scrap my performance recording in that instance - live lambs are better than performance-recorded dead ones. Mismothering should be fairly obvious and sadly, outside there is little chance of getting a ewe to take back a lamb it has rejected. Cull any ewes who mismother and do not keep offspring as replacements, as there is evidence mismothering is learned in the first few minutes of life. Hopefully, you will have chosen some decent ewes and mismothering wont happen very often.
Once you have chosen your system stick to your guns. My vet told me some horror stories last year about people who (rightly) had gotten worried about the wet right at the last minute and brought all the ewes in, they then had a series of complications at lambing and a lot of watery mouth etc after and ended up lambing at 70%, compared to my 185%. My 'go-to' book is still VSS's book - you just have to remember it is written from the perspective of a March based lambing system in the uplands of Wales. The author is kind enough to say at the beginning of the chapter on lambing that if you were to lamb in April it would be a no-brainer to do it outside. There is a real danger of it being too warm to keep sheep indoors in April - increased temperatures are good for infectious diseases.