Woollyval said to make him sick but I was under the impression sheep can't vomit.
We asked the vet about that and he said that ruminants can't vomit. Vomiting is expelling contents from the stomach - ruminants don't have the muscle structure round the rumen to expel the contents. What they may do is regurgitate stuff from the oesophagus, which DOES have the right muscle structure - so it looks like vomiting but technically isn't.
The poison was affecting the oesophagus - Dickie couldn't swallow, which was why he was foaming at the mouth. He wasn't producing more saliva than normal (ruminants produce a lot of saliva) it was just that he couldn't swallow properly.
I think this accurately reflects what the vet told us. So much to learn
But Dickie is fine now. Happy to be back out on the grass, although last night, when I went through their paddock to shut in the hens, they tanked up to the gate behind me - don't know if they fancy having nights in and days out