Looks like she only has 1 utter too. If she has twins (which I doubt she will) should I let her try to feed both?
No. The ewe will make as much milk as the lamb(s) take. If 2 lambs are drinking from only one side, she will increase her milk production to feed them both.
Did you get her fully grown and had she lambed previously? She looks like she had a case of mastitis resulting in the loss of one half her udder. We were given an older Suffolk ewe one year that freshened only half her udder due to mastitis. She raised twins on one half of her udder. In spite of treatment for mastitis our ewe never regained any use of that side. Since she looks like she has quite a ways to go before lambing, you could treat her now for mastitis with a
dry cow formula. You can either buy it at your local dairy store if you have one or order the infusions from any dairy catalog.
She won't like being treated at all, since even dairy animals that are used to being handled and milked daily hate it. The infusion tubes come in plastic tubes that look like mini horse worming tubes. They have a plunger applicator and have a very thin plastic tip to put on the tube. You have to insert the tip of the mastitis infusion tube into the teat end and squirt the contents into the teat and udder. Then massage it around and leave it there until she freshens. Probably not comfortable for her. You will have to restrain her well to get it done.
If she freshens with a case of mastitis you will have to treat her with a
lactating cow formula and will not be able to use her milk for the lambs for whatever the withdrawal period says. If she has already lost half her u dder to mastitis she will probably freshen without mastitis in the remaining side.
If you decide to let her freshen without any treatment - which is fine too - then just make sure that if she has twins that each of them get colostrum. With 2 udder halves each twin gets their share easily, but with only one working teat they will have to take turns. This will be ok later but right after lambing you might need to help the second twin get its share of colostrum. If necessary you will have to put her in a small pen so you can catch her easily when she lambs. then halter her and tie her to the pen while you switch off the twins to make sure they each get a share of the colostrum. You will not need to supplement them, unless you notice that she is pushing one of the lambs away and refusing to let it nurse at all. If you do have to bottle feed one, make sure it has colostrum for the first couple of days I suggest you put the
ewe lamb on a bottle That way the keeper ewe will be tame which will make it easier to work with her in your flock.
Hope this helps.