Hi, thanks in anticipation of any help; I'm a new chicken owner (having only had my 5 girls for a few months). They are all healthy and active but one of them has yellow runny poo (looks like mustard!) Some days there is none in the coop (just the normal looking poos) and other days there is the yellow stuff. I let them out of the run today and watched them in the garden for a good 20 minutes and watched one of them drop this yellow runny stuff! She seems fine otherwise. Any ideas?