Thanks for the reply guys yes she is normal in all other ways and is actually the healthiest looking one I have
Worth mentioning that frequently letting the gastrointestinal system clear out completely is one of the main traits you find in all healthy and long lived domestic species, pretty much. The digestive system remains at its healthiest when it can clear out for even a short time period on a regular basis, and therefore rest and regenerate without interruption.
All health hinges on the digestive system, you've probably heard of the studies on animals of multiple species showing that animals that were fed less rather than more, as per the usual intermittent availability of food sources for the species in the wild, live longer with fewer health problems.
In the past, and even in modern times, many poultry-keepers valued these 'fasts' for supporting full health and knew their value.
Unfortunately many people panic if a chook doesn't eat and forcibly cram things into them, which when an animal is already sick can be fatal to them. (Of course, it can be lifesaving too, depends on the things being force fed to them and the problem they have, but it's a fine line to tread).
Fasting is beneficial to total health in moderation and correct timing.
I'm not suggesting you fast them, just that it should be more widely known that it's not always a sign of illness for an animal to choose not to be stuffed to the gills; fasting is a natural reaction to illness and sometimes injury which allows the system to focus all resources on tackling the problem and healing faster, rather than always being a problem in itself.
It's also during the night time that animals with speedy metabolisms naturally fast, even chooks of metabolic types or breeds that 'stock up for the night' are empty by morning if reasonably healthy, almost as a rule.
Best wishes.