Mites and Fleas

Hi Spanish Girl, Where are you? The link is spot on, but, given the weather and availability of treatments, people here might give additional information or caveats.

Surprise! North or South? i.e. warm or cold at the moment?
Try to be logical, just as you would if you were being bitten yourself. Try to look at the birds and their coop for the creatures. A bar of soap will catch some so you can compare them to the photos on the link. Look for blood in places such as the underside of perches.
Watch their behaviour; fleas are quite large and may jump; lice are slow moving and mites move very quickly. The big difference in treatment lies in where the creatures live. Mites do not live on the birds so you need to look at the perches, bedding etc (although you might find some on the birds - and on yourself. Fleas also live close to the host rather than on it, but lice will often stay on the host. The link gives ideas on specific treatments and there are lots of posts on red mites.
If you are not sure and remain bothered, then go for the blitz. Clean out all bedding and burn it. Remove and clean anything not fixed. Wash out the coop using hot water, detergent or bleach. Pay attention to all joints. Allow to dry then spray inside and non-rainwashed areas with Ficam. Allow to dry. Mix a slurry of diatomaceous earth - to make a muddy paint and paint it onto all the inside of the coop. Allow to dry. If the outside has gaps or roof covering like roofing felt that insects can get under, it would be best to repair or change these, but if you can't do this then spray Ficam under the felt.
If it's not too cold you can give them a bath in warm water then blow dry with a hair dryer. A small amount of dettol is fine in the water.
Clean the area around the coop, removing all top litter. Change your clothing in the bath (not just the bathroom) and shower/wash hair. You'll not be popular if you introduce fleas to the bedroom - I know from experience having done just that!
If you have animals such as cats or dogs, you should treat the area where the cats sleep and bathe the cats, but do NOT use Ficam. Fleas in the house do not move far, so a good move is to regularly vacuum the area where pets are allowed.

You can see why I asked about where you are because drying is the key to moving from stage to stage.

Hope this helps, but please come back.