Actually I don't want to put anything disgusting in here, but those kind of unpleasant things are my job fields.
I just wanted to share what I had several weeks ago.
Some farmers may not notice this parasite infestation on their birds, but this creatures does makes anemic, may result on poor weight gain and even lower egg production. There are some antiparasitic to eliminate these small little things. But the application has always been the main problem.
If you want to see if your chicken has been infected by Red Mites, open the wing or just around the cloacal area, you could see them there pretty easy ( Not so easy though, maybe some help of magnifier) and red mite is a nocturnal parasite.
Here is an example of heavy infestation of red mites.
Warning : This may look unpleasant