Grooming or Lice

They will groom (preen) lots anyway, and they will dustbathe whether they have lice or not - they enjoy it! They are also extra itchy at moulting time. However, if a bird seems to be bathing several times a day, every day, and often "itching" at the tail end, chances are it will have lice. A good clue is to watch them eat their end of day treat, and if they have to break off eating/competing for it to have an itch, then chances are they have lice. It's easiest to check them over at night, when they are on the roost. Go into henhouse after dark with powerful torch, grab a hen, upend it (holding legs firmly) and search to the skin through all feathers around vent, between legs under and around tail. The lice are amber coloured, about 2 mm and scuttle away from the light. Any eggs will be cemented to the feather shaft close to the skin. Treat with louse powder according to tub instructions and re-check/treat after 5 days to catch any lice emerging from eggs (most powders only kill the lice and not the eggs). Hope this helps.

I love to see a bird preen itself. I always take it as a sign that the bird is well and happy. A sick bird doesn't bother to preen. They are probably just taking good care of their feathers. It's important to keep themselves in good nick. You can check at evening as Richmond Hens says, but they are probably just looking after themselves like good girls.

Thanks,
It did look like just having a good preen as occasionally they'd just close thier eyes and enjoy the sun, I just had a bit of paranoia set in as they were all at it.
Thanks for putting my mind at rest

Been there - had the paranoia. Still get occcasional bouts if I don't lie down often!