Mina

It is generally good practice to spend time with your flock on a regular basis (as if you don't already!), apart from the regular feeding and cleaning, but really observing them, so that you know what is 'normal' and immediately notice any changes in appearance or behavior. The faster you can identify a health issue and treat it, the better. Chickens, being the ultimate prey animal, are masters at hiding symptoms and often by the time you notice something is wrong its too late.