If these tiny pale creatures are moving about during the day they are actually a different mite to red mite, but equally annoying. You will find they are quite active on all surfaces while red might tend to congregate underneath and do not usually move much during, unless greatly disturbed.
If the red mite haven't fed for months they will zip out and/or fall onto the first source of warmth they encounter, in the hope that they can grab one of the blood meals they need to develop into the next stage or lay eggs. In this case the potential dinner is you.
I can assure you there are red mite and grey mite found in poultry houses and they are 2 distinct sorts.
Where red mite are present, along with birds for them to feed on, you will find the engorged red mites in clumps under perches etc. These, when well fed will not move during the day, unless disturbed. At the same time you will see the grey mites wandering about on any surface, and not necessarily anywhere near the perches. The grey mites are not blood suckers and appear to feed on debri, not on the birds themseves. They are like large dust mites. They have a horrible habit of crawling onto you if you touch surfaces where they are present and you can spend many a happy hour trying to get them off you.
I am not disputing that red mite, when not fed will also appear grey. I am merely pointing out that grey ones active during the day are possibly another sort, and are easily controlled with permethrin.