In our experience lambing on pasture is a matter of balance. There are advantages and disadvantages. We appreciate it because it's simple and it's natural.
Advantages
Ewes are birthing when there is a spring flush of grass so do not require extra feed. During the time when their nutritional needs are highest, nature is providing what they need.
This means that during our cold season, when we're feeding hay, our most expensive feed, we're feeding ewes who are at a maintenance level of feed requirement. We do not need to feed grain and expensive supplemental feeds.
Birthing difficulties have almost disappeared. With nutritious grass and necessary minerals the ewe's uterine muscles remain strong enough to move the fetus into proper birthing position.
Mis-mothering (ewe's not knowing which lamb is theirs) rarely happens provided the animals have enough space.
We don't worry about catching newborns and spraying navels. We relax knowing the young are born on clean ground.
We often see ewes on grass raise twins with little trouble and feel this is about perfect. Occasionally we see triplets. However, even an efficient, healthy ewe that raises a dandy single is still welcome when there is little or no direct costs in raising the single.
Lambs that are birthed on pasture begin to eat grass sooner than those who are birthed in a corral or dry lot and started on creep feed. Grass combined with moms milk is the best combination for healthy, robust youngsters who gain weight at an appropriate rate.
The lambs rumen is developed through eating grass not grains or feeds that can alter the state of the rumen.
Not forcing weight gain by feeding grains. Pushing for weight gain too fast alters the normal growth and hormonal development of animals and will only hinder the flock in the long run.
No building infrastructure is required.
Overhead costs can be substantially diminished.
Even if we figure in the extra dollars we might earn from marketing winter born offspring it does not cover the cost of the extra feed and man hours spent in the barn when birthing in the winter.
Disadvantages
High birthing percentages that barn raised flocks accomplish are not realized on pasture. This can be partially attributed to how different breeds of sheep perform in each situation.
Out of season breeding and accelerated lambing programs are suited to barn raised flocks where every detail can be controlled. With lambing on pasture pasture we cannot participate in these avenues.
Only sheep breeds with high milk production will support multiple births. That high milk production means that ewe is less than efficient on feed and requires extra to maintain herself and produce enough milk for three, four or five babies.
Yes, the sheep predator is a disadvantage. He does grab a meal occasionally, but as it turns out, the coyote is not as hungry during May and June as he was earlier in the season with the extra demand from pups.
Some sort of predator control is needed. A flock raised in a barn will not see the same predator pressure as the flock on pasture one mile from home.
Fencing is required or a hired shepherd to control where the flock goes.
Contrary to popular opinion lambing does not have to happen in a barn. Yes, if it is cold and wet outside or if you chose to birth during a Canadian winter, newborn and young animals will need a barn of sorts. Most distressing to us though, is that more and more often we come across people who believe sheep HAVE TO give birth in a barn.
Also contrary to popular opinion and curiously enough, held most often by those who have never raised sheep, the young are not born to die. People however, are doing sheep a disfavor by raising them as though they were.
We feel that ewes who don't know what to do on their own and babes weak enough they need support to stand up and suck are poor representatives for the whole. We prefer to see healthy, robust newborns that will be up and sucking without interference from us.
While we know pasture lambing will not suffice for everyone and even downright scares some people, it takes less time and effort for us that we actually look forward to it. We enjoy the freedom to sit for an hour and absorb nature at its best; to hear newborns bleat for the first time and witness young animals exploring a natural environment.