I am taking care of my neighbors guineas while he is out of town (which is quite a lot). He had 18 of them in a large pen. They have been there since they were little keets and they are adults now and laying eggs in the guinea house. All of them seemed pretty healthy but recently we found one dead in the pen. No marks on it, just dead. I am wondering what worms or diseases might be prevalent among guineas. Any experience in this?