I'm fairly new as well but I have had two different outcomes with the same standing still like their sleeping but will also walk, lay down, stand but doesn't really move much continues to stand still for most of the day.
My outcome for the first 3 of them was Marek's but that had the addition off watery poo with small bits of green in it.
they succumbed to the disease within a week of symptoms.
My last girl was, Thank God, just egg bound and had all the same but still had good poo. within 3 days she had passed her 2 weird eggs and is back to normal laying daily.
The combs will also let you know they aren't feeling well.