but I have to say Raisen is a cool name for a chook!!!
Yes, and Rum is feeling very lonely now, having lost her other half :-(
After a bit more research, I think little blue may well be right with coccidiosis. I had initially discounted this because she is quite an old hen, I'm sure she should have been vaccinated when she was a chick, and there was no sign of blood in her droppings. However, a couple of websites do say that yellow poo is a sign, and she certainly had that. Also, the timing being just after the worst of the cold weather might also be a sign (the infectious oocysts apparently don't like extremes of temperature).
I have to say though that if it is coccidiosis, I haven't a clue what to do next. I'd even struggle to dose their drinking water, since the hens all drink out of the burn normally. As usual, any ideas folks? We have eight hens here that have lived here for years, four of ours that came with us when we moved, and thirty six week old hubbard table birds. Should I be concerned, and is there actually anything I can do about it other than just keep fingers crossed that the others will have built up an immunity?
Cheers!