Jon’s up in my old neck of the woods, so I assume is feeding Jim Peet’s or Tarff Valley’s “all stock” mixes, which are 15-16% protein and are safe for sheep, including male sheep. They don’t contain copper.
However, a whole Pot Noodle pot per day per sheep is a quite a lot of hard feed for a Shetland lamb, isn’t it? I think I might halve that. I wonder if too much hard feed might make a sheep not eat enough hay to keep his digestion working properly?
Now they’re on hay and hard feed, they will need fresh water available. I’ve found that, unlike cattle, sheep can be quite picky about their water, and won’t drink unless it’s fresh and clean. So if it’s a bucket, it might need to be scrubbed out every few days, and the water replaced every day.
I hope you have talked with the vet by now, Jon, and have a way forward.