dead guinea, any ideas why?

[birdbrain5]

its been hot here lately in NC, but today is considerably cooler than the past week. my guineas coop at night, and are out from early morning to whenever they go in. theres always a big tub of water refilled twice a day for the ducks right close to them, plus the water buckets for the sheep and horses available, and they have range of at least 5 clear acres but a total of 10 with woods. they dont range far enough to be out of sight, but still plenty of room and bugs to eat and i sometimes throw seeds and chicken food for them but mostly let them fend for themselves although i know some people may have a different opinion on that. i know many people around here that have flocks of guineas they never coop or feed, they totally fend for themselves and do just fine. this morning one of the guineas (all that range are a year old or so) was letting me get real close and i thought that was a little odd, so i went to pick it up and it wasnt thrilled but i was still able to. i brought it over to the water and scattered some food for it and it was just laying there so i thought maybe if it was a female it could have been confused and laying its first egg. i checked on it again in a bit and it was still in that area, so i picked it up and it got away from me and kind of fell. i then put it in the pen with food and water, and left it for a bit. i just went out to check and it was dead. i have no idea what may have happened. i thought it was a male at first but then i think i saw this one making the buck wheat so it may have been a female. hard to tell they all look alike. what could have happened? i know some people will cut thier birds open or inspect to see what went wrong, but i get squeemish with dead things and i couldnt bring myself to do that. all the others are out rangeing and seem fine. its just odd, theres nothing around for them to get into as far as poisonous stuff. the only other thing i see them eat is the grains from the horses that they drop, but its really not alot. any ideas?

 

[PeepsCA]

Any overheated cars with leaking radiators leaving puddles of antifreeze around that the bird coulld have had a few drinks of? No rodent baits, bug baits or pesticides used in the garden or flower beds that it could have gotten into?
Could it have possibly been a head injury from hitting the wall or ceiling in the coop maybe? Sometimes they can take a pretty good crack on the noggin and it barely leaves a mark, then after some brain swelling they end up dying.
Did the bird have an impacted crop?
Sometimes the heat just stresses the birds past what they can handle, so who knows. Without a necropsy it's impossible to know the cause of death, and even then sometimes it's still unknown.
Sorry for your loss, hope you don't lose any more!