This happened a while back, but I was curious to see what happened. I had a hen that resembled a Brahma that was fawn colored. Well, I had decided to let all my chickens out to pick at the yard. She was doing fine, eating drinking the water. Well, I looked over and she just stopped in the middle of the yard, fell over and twitched violently. Sadly, she passed on a few seconds after. Does anyone have a clue of what happened so I may prevent it in the future?