Lost 2 of mine last year with it .... out of about 5 affected. Vet said it didn't take a lot to be fatal. Sorry.
One showed symptoms much earlier than the others and we lost him that evening. I don't know exactly when he ate the rhoddie ..... sometime after 10 am and found him with obvious signs of poisoning by 4pm.
Others looked fine at that point. Vet warned us to watch the others as they too could be poisoned but eaten it later or not eaten so much. They were showing signs by next morning.
Vet did inject the first two affected with painkillers and something else .... sorry can't remember what. He did not treat the others .... said there was little point. I think he thought they would all die. Don't think he was keen on treating the first two to be honest but did because I was keen to do all we could. He said to put worst affected under a heat lamp and away from draughts ... was October.
He said there was no antidote.
He prescribed 'Life Aid' and said to drench as instructions on box.
We also gave strong tea and activated charcoal.
for your sheep. Some of ours did recover and seem fine now.