Straddle her facing her butt and reach around her placing your hands on her abdomen just in front of her teats on each side. Press firmly, first with one hand and then with the other alternating pressure left and right. If she is four months pregnant you should be able to feel the lambs about the size of newborn puppies of a medium to large dog. If a single it will be dead middle if twins there will be one on each side . You will be able to feel the skull knobs as the largest thing. Little knobs are knees and hocks. If you find a whole lot of knees and hock bumps (about quarter size) you may be looking at triplets. They would be placed one central and one to each side. I can tell for sure mine are pregnant this way by the fourth month. It usually takes me to the fifth month to be able to tell between triplets and twins. I have a lot of Finn blood in my sheep and it is not unusual for me to get triplets if I have fed the girls well.