They are in an area of about 2000 sq.metres along with chickens, geese and ducks. We feed them a grain mix/layers mash in the mornings and corn in the afternoons, and throw in grass from the garden. There are orange trees and olive trees in the pen. This has not changed. The symptons are that they stop eating and become less active. Then they die a day or two later - it seems very quick from the first sign that they are unwell. I don't know the breed name - they are mostly black, with a few bits of white and we have two pure white ones. Their poo is loose, but not like water. I have penned them off and am feeding them 'baby food for poultry' - we are in Crete so I don't know the equivalent in England. It contains some medicines. I have also added Baycox to the water from yesterday and I think they poorly looking two have picked up a bit today. Some strive and others die.
As I said when my husband looked into the insides of the ones that died their intestines seemed swollen and smelt bad.
I am hoping that the Baycox is doing the trick, but I would like to know what the cause of the problem in the first place.