I found my 2 year old speckled sussex dead on the floor of the coop 4 days ago- we didn't notice any signs of illness before her death. Two days later we noticed our 3 year old white rock hen was lethargic. We separated her from the others. She does not move and seems to just stand there when I take her out of the cage she is in now. She has not laid an egg in at least 3 days but I do not believe she is eggbound. She drinks water but is not eating her food but she ate the apple cores and bread we gave her yesterday. Her poop was like liquid yesterday but since it is hot here we have been giving the chickens watermelon and this often causes watery poop. Today her poop is more normal consistency with the typical white in it. She lives in a coop with cement floor about 5x5 with 3 other hens (it was 4 but now 3). We have not introduced any new chickens but we do have two 8 week old Salmon faverolles that are living in a cage in the garage until we introduce them. They have not been in direct contact with the ill hen except that we let them play in the adjoining run of another coop approximately 8 days ago and it is possible that the ill hen went into this run after they were in it. The chicks are not ill and the hen that lives in the adjoining coop is not showing signs of illness but she is broody and is not hanging out much in her run. I do not worm and have not seen any signs of worms or mites. I did a thorough cleaning of the coop yesterday. Any help is greatly appreciated.