All of which just goes to show that if you ask 4 farmers how to do something, you'll get 5 different answers!
sheep will isolate themselves from the flock to lamb
Agreed. But she only isolates herself when she is going to lamb, not usually several days before. What she does do, and will do indoors too, if she is allowed, is select her spot. They do this in the communal pen too - I do agree that it's more natural for her to be able to get away from the other sheep to lamb, but they do choose a spot and start preparing it, scratching at it and so on, some time before they start to lamb.
Its a lot easier to control and monitor feed intake and you therefore have a better idea of when lambing is imminent
I find it pretty easy in an open pen - a ewe who is imminently planning on lambing may well hang back from the trough, enabling you to mark her and keep a special eye on her thereafter. However, I have many a time seen mules of mine troughing away with the rest of them, with water bags and even noses and toes sticking out their backsides!
So you don't always get that loss of appetite to alert you that they are thinking about lambing. One thing I do like about feeding them all together at a trough is you can go along and look at backsides and udders while they're stood still - also very helpful in determining who may lamb later.
One thing that has occurred to me is that I make the assumption that anyone lambing sheep indoors is available and planning to do two-hourly - or at the very least four-hourly - checks throughout the day, and night too if necessary. If your setup is such that you have to leave the sheep alone for longer periods, then I can see that you may find benefits in having them penned individually before they lamb as you would not be on hand to prevent some of the problems occurring that would do so in a communal area if the sheep were left alone for long periods while lambing.
I have to say it would not sit well with me to leave lambing ewes unattended indoors for long periods, however they were penned, but I realise that's easy for me to say as we are full-time farmers, and perhaps it's unrealistic of me to think that all sheepkeepers, on whatever scale, can and should provide the same level of attendance at lambing time.
sheep lie on their lambs on purpose, not by accident, pen size has little to do with it
I couldn't disagree more, but that's my personal experience and clearly yours differs.
what would you describe as overlarge? how do you think sheep that lamb outdoors manage to keep their lambs?
That's the thing - we've taken them out of their natural environment and put them in one which is more or less completely unnatural to them. They do not behave the same indoors as they would out in the field. If we always had good weather at lambing, I'd leave all sheep to lamb outdoors, with the possible exception of twin-bearing first-timers. Outdoors, a ewe who is unhappy about a lamb's questing little mouth around her underparts can simply move away. Instinct and smell bring her back soon enough, the lamb tries again... if the weather is kind, lambie will usually get fed eventually. Unfortunately, if the weather is
not kind, lambie could founder and die before mum gets used to the idea. So we bring them indoors. In my experience, the incarceration and stresses it brings tend to make ewes even
more disinclined to let their lambs suckle, especially first-time mums.
If you pen her in an individual pen for lambing, and aren't there when lambie starts trying to suckle, when she's already stressed by the situation - you may arrive to find a dead lamb, killed by its own mother, stressed off her head and battering it. If she lambs in the communal area, she has the option of moving away from the lamb and coming back, as she would outdoors. She's less likely to kill the lamb. I do agree that there are downsides to this situation - another motherly ewe may pinch the newborn lamb who is crying; by the time you get there its natural mother has produced another lamb and is mothering it, so you think you've had two ewes lamb; later on motherly ewe has her own lambs and then goes off the one she pinched... etc etc. But if the space and stocking density are right, the checks are frequent and the staff experienced, on the whole, my preference, and I am pretty sure general practise, is to lamb in the communal area and pen once licking and some bonding has occurred.
As to the optimum size for a 'mothering up' pen, which is what most of us use a lambing pen for, my preference is for an oblong pen in which the short dimension is about the length of the ewe and the longer dimension gives room for the lambs to get out of her way, so 18"-24" longer than the short side. If I have a ewe who is being aggressive to her lambs, I like to have a shelf or creep area the lambs can get into to get out of her way and be safe from battering. I also prefer a longer pen for triplets, as my experience is that a large ewe in a small pen with triplets is quite likely to flatten one, and is not likely to flatten one at all if she has enough space.
The reason I like the pen that size and shape is (a) I can catch a ewe very readily in that size of pen, and can tip her up if I need to without squishing the lambs; (b) it's large enough for the lambs to get to safety but small enough that if the ewe is a bit iffy about letting them suckle, they can catch a few sucks here and there as she feeds, drinks, etc. Even if she twizzles away from them, they get pretty adept at jumping back on as soon as she stops spinning around. In a larger pen, it's very much harder for the lambs to get plugged in, so they are far more reliant on you attending and restraining the ewe in order to get a drink. In my experience, more ewes settle to their lambs without much human intervention (other than penning them) in a smaller pen than do in a larger one. In the latter case, I expect to have to catch the ewe three or four times to let the lamb suckle, whereas in the correct size of pen I may only need to show the lamb where the teat is and the lamb does the rest. In my opinion, the more human intervention there is, the more the ewe dislikes the lamb feeding, so it takes longer and is harder on us, the ewe and the lambs. I am perfectly happy to be told that it's different in different systems and with different breeds, but my experience with hill and hill-derived commercial sheep is as described.
its a lot less stressful on mother and lambs to leave them alone once they have lambed instead of chasing them round a pen full of other sheep to put them in an individual pen, which can lead to its own problems, especially with young ewes
Again, I can only describe my own experiences over 7 years now of lambing around 3000 sheep overall, of which perhaps 500+ lambed indoors, but my experience is that it's pretty easy 98% or more of the time to get the ewe to follow the lambs to the lambing pen, provided you leave her alone to lick them and start to bond before you start moving her. I think I can probably count the number of times I've had to chase a lambed ewe around the lambing pen to get her penned up with her lambs on the fingers of one hand. Okay, maybe I might need the other hand but I certainly don't need to take my shoes off!
(Mind, I am also pretty cunning now at manipulating sheep into being where I want them.
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But yes, of course it would be nice to not have to move the ewe and lambs at all. I can see that your experience with your sheep is that it is better to pen them individually before they lamb, and that's fine for you. However, I think that this approach is not the norm, and I think there are a number of reasons for that, of which I have enumerated some. novicesmallholder Mark will have to make his own decision about what system he is likely to use and therefore what size and shape of shed and lambing area he needs to plan.