Daisy,the second rabbit we had was an english and she never produced normal poohs, we go her from a pet shop at about 8 weeks. We assumed these were normal for a young rabbit- she came to partner Benji, our wild rabbit and I just thought he was different as he was wild. Anyway she had a severe dose of diarrhoea and died,we got a post motrem done and she had clostridium in her liver, which was said to have caused her death. I know cats and dogs get an illness like grass sickness in horses and clostridium has also been suspected in this. The big problem is it could be caused by a number of things, certainly they have been trying to figure out what causes grass sickness in horses for years, clostriduim, cyanide from clovers, selenium deficiency and the affect of drought and temperature on the grass has all been suspected. This doesn't really help but it may give you some ideas to work on.