As stated at the start of this thread it is quite common for both Blackheaded and Olives to pass small amounts of green urates while being cooled down over winter. Its nothing to worry about.
However, if they start oozing large green puddles all over the enclosure you do have a major problem. In the good old days this was always believed to be caused by amoeba in the gut and would be treated with flagyl. As the treatment just about never worked green meant death.
Some 20 to 25 years ago I had a string of BHP's die with the green urates. Peter Noswothy of Wyoming vets found that every one had died of fatty liver desease, but he had no idea why. After throwing some ideas back and forward I suggested could it be the diet,eg fat rats, as these snakes mainly eat lean reptiles in the wild. He agreed this was more then likely the cause. As there was no cure we decided FLD could probably be prevented just by feeding leaner younger rats. This worked well. I spread these findings around the herp world and now it is common knowledge and has probably saved the lives of thousands of BHP's and Womas.
Some 10 years ago one of my workers, without me knowing, was feeding a female BHP large rats. The result FLD and bad. Mark Simspon, a vet from Wallsend asked could he look at her and tests confirmed her liver was gone, and that there was even green bile in her blood. Even though I thought no hope, Mark wanted to try a drug designed to remove fat from sheeps livers. I left her with him and months later she was back home and completely cured. So the is now a drug that may cure FLD. As for the drugs name and dose rates, Mark Simpson would have this imfo.
Garthy If it is just a BHP or a Woma leaking green its more then likely FLD. But if other species start oozing bile its normally for another reason. In a single specimen I would be looking as amoeba or flagylites, but when multible snakes and species start dying from it, one suspect leaps to the top of the list. Salmonella. Freezing food does not destroy Salmonella as it does with parasites, so a bad batch of rats could easily be the cause.
I have had Salmonella outbreaks in the past caused by using poultry to feed my snakes. For this reason I never use chickens or turkeys to feed my snakes. There are so many strains of Salmonella, some not so bad, some deadly, some not contagious, some highly contagious. A good tip is to make sure if you are purchasing your food make sure the supplier has a good name and never use poulty no matter how cheap it appears.