they are free range chickens, The older ones run around the fruit orchards, the mums and chicks get moved to a separate pen once they are born as there is a furrow that runs through the orchard, and fear of drowning is too high. The new mum and her 12 chicks were put in the pen with another mum and her 3 chicks on friday. We lost one chick on saturday but didnt think too much of it. The others were all healthy eating etc, I fed them went out and when I can back 8 were dead on the floor. they all eat the same food, have water, shelter etc.... Is this common to lose such a high number in one hit?