First sick chicken (maybe)

Hello all! I'm fairly new to chicken raising - we just got our girls in July, so they're all about 8-9 months old. All hens, no roosters.

My brown orpington had a lot of poop stuck to her butt. Gave her an epsom salt bath, blow dried her and trimmed the very caked feathers away. Her vent looked good - not red or swollen at all.

I hadn't actually seen her stool until I brought her back outside with the rest of the flock. She shot out liquid poop (sorry for the description) into the grass so I couldn't see much other than the consistency being very watery. She also seems to be moving more slowly and kind of has poor balance it seems from time to time. She is still foraging, drinking water, and eating to my knowledge.

Is this something I should be worried about/try to treat? Or should I continue to wait and see.

I'll also mention that temps have plummeted here recently (we're in Denver), so not sure if that might have something to do with it?

Thank you for your input!