The only lambs I've had to top up since I switched to Shetlands, Manxes and crosses thereof, have been triplets where I thought the mother had insufficient condition to feed three.
I do the opposite of flushing, but nonetheless, Lessa (Shetland x BFL) had triplets more often than not (and always reared them herself if given the option, even if I helped a bit for the first few weeks), and this time, when I confidently expected no triplets having retired Lessa The Wonder Sheep, blow me if Minx (Manx x Shetland) didn't decide to come back fighting after a poor year in which she lost one lamb (to pneumonia at about 8 weeks old) and stopped feeding the other a few weeks later. Maybe she had heard me say I would give her one more chance, as she had been just about my best sheep before last year, and is still a young ewe from an excellent dam. I shall have to explain to her that 3 isn't better... but she's doing them well so far, without any help, and has plenty of condition and we have plenty of grass, so
I am ruthless in culling or retiring ewes which can't or won't mother, although I give them all a One Shot Pass for the first year, so long as all they needed was help getting used to the feeling of the lambs suckling the very first time and maybe, if they are otherwise exceptional sheep, for two feeds.
I had 3 first timers lambing this time, all homebred Shetland crosses. 2 (1 Manx x Shetland and 1 a bit of a mongrel 1/8 Icelandic, 1/16 Dutch Texel and the rest Shetland) did brilliantly, no help required at all, but Gwennie, Zwartbles x Shetland, who lambed first of the three, was an absolute pain getting her to let the lamb suck the first time, and the second, and the third... (Despite her mum Gwenneth being the best motherer of all our Zwartbles, never gave us a moment's problem, not even as a gimmer, and reared strapping twins every year, hence why I kept on one of her daughters). Gwennie then pestered and scrapped with the next ewe to lamb (also a gimmer) a few days later, so Gwennie is on the cull list, and that will be it for Zwartbles blood here. Give me primitives every time!