What could cause a rapid loss of weight then disorientation and death in both a duck and chicken? Both had been very healthy and fit days earlier and seemed to go downhill overnight. We're at a loss as to what could have caused this and my books aren't helping! I dust for mites and they have access to fresh water and a pelleted complete diet. Both chicken and duck had houses and open, secure runs as well as daily times outside on grass. We have horses and they like to scratch around in the horses' grass fields and in our yards. We do have some mice but have not put out poison. These were robust birds that seemed to overnight drop to skeletons then, sadly, die. Literally, one day were running around like they owned the place, eating well, and looked quite plump. Then in the next day or so starting faltering and, when picked up, had no meat on their bones. I handled at least the chicken frequently (reorganizing the roost at night). What could be going on?