I like my system. Shetlands, no hard feed, just hay and a mineral block, or if it's especially deep snow for weeks when in lamb, a bucket lick.
Inexpensive to buy and keep.
Ok they aren't worth much to sell. And a vet visit means an automatic loss on that animal even if it's cured. However, if it doesn't make it, the money written off might be £30 not £100.
No birth interventions, ever. No losses post birth. Only one ever having to be helped as a bit dopey (tuned twice and then fine). No abandonments ever. 150% lambing year in and out.
The value doesn't matter so much when they are mainly raised for us and friends and family. (tho having to sell some this year as they all keep producing ewe lambs which I prefer not to eat if it can be avoided). And the most amazing lamb and ESP hoggett.
Have too many ATM (45 altho that does include 6 Herdwicks and their 3 Herdwick x Ryeland lambs (they're funny looking bruisers :-)) so will be reducing soon, but I will def retain the core herd!