Chicken Upchuck?!?

[Hill Salt & Rox]

One of my chickens threw up! It's around 100 degrees today and she was walking around outside with her mouth open. I thought it was because of the heat and she was just trying to cool down. A few minutes later she bent her head down and a fluid came out of her mouth. She then drank some of it. Before throwing up she was acting normal, she did not heave or make any noise. After drinking a bit of the throw up, she walked off with her mouth closed and acted perfectly normal. If I had not been watching her, I would have missed it. I did not know chickens were able to puke and think it is a way for her to get rid of water faster so she can drink more to cool down. However, after upchucking, she did not drink any more water. We have lots of shade and fresh water provided for our chickens and none of the other chickens were acting as if they were hot. Is this normal? What do I do?

 

[MillersFarm]

Chickens do not vomit. Unlike humans, they don't have the ability to upchuck the contents of upset stomachs. So, when you see fluids come out of your hen's beak, something is very, very wrong. ... Your hen might have sour crop, which is when the crop isn't doing it's job, and yeasty, sour-smelling liquids accumulate there.

 

[Fanci Feathers Marans]

I have had some chickens throw up on me when I picked them up (upside down). They don't heave, just use gravity. I'm not totally sure she's sick..