Thanks Lordstark, please do keep me posted.
I checked out the link, my Nugget's vent doesn't look anything near that nasty? More like a bit dirty from passing the poo. I saw a bit of runny poo in the run this morning when I was just leaving for work, but I'm not sure if it's because I gave them lettuce? I heard lettuce can make poo a bit runny sometimes?
They were all bright and alert this morning, and had a healthy appetite. I gave them more cooked mince and scrambled egg. No diarrhea in the coop overnight. Will keep observing.
I felt their crops tonight (didn't pick them up as I got home too late and they were already settled, I didn't want to upset them too much) and they all felt full and normal.
The weather is getting cooler here too, especially at night. Does anyone know if I need to put the thin moulting girls inside where it's warm (like in a box in a garage with heat lamp outside the box), or would they be ok in the coop? They're still eating, comb looks normal, no messy diarrhea that I can see.
I keep worrying now, really don't want to find another dead chook in the morning!