Crossman,

Its generally a low risk hazard but some factors to consider are;

Condition - wet or dry with dry more likely to get airborne and be inhaled
Who is doing it - those with breathing complaints may be more at risk
Concentration - confined spaces will concentrate the material
Method of cleaning - power washing will wet the material but also lift it and make it airborne
Hygeine - dispose of or wash clothing after use, maintain good hygeine standards and consider concentration as to whether you need a respirator.
Disinfect the area with a suitable disinfectant after cleaning

I keep chickens so have similar problems relating to cleaning

Before becoming a Health and Safety professional I used to deal with the removal of Pigeon Droppings.

There are a lot of myths in relation to this as the media and pest control companies seem to over hype the inherrant risks. It is highly unlikely and virtually nil that a human will contract a disease from the removal of pigeon droppings but there is still that inherrant risk. What I would suggest is that you look at how much pigeon guano that the individual is removing and assess the risk from that approach.

The way that I used to operate was for small amounts of feces then the individual cleaning the area would need to wear gloves as a minimum. For larger quantities where contact with clothing or boots came into effect I would use disposable coveralls, gloves and boot covers as this would protect the individual from getting the feces on them as it can be quite unpleasent. If the area wasnt well ventilated and the smell was really over powering then maybe look at other possible PPE.

If you want any further information then please pm me and I will try to help.

In the wider context, risk assessment should consider measures to preclude roosting. There are some very simple and cost-effective methods out there.
For dry guano, why not a FFP mask?

This is worth a look too - although 10 years ago, it nevertheless shows an improvement notice is a real possibility for failing to carry out a risk assessment for pigeon droppings:

www.hse.gov.uk/noticeshi...Notice_details.asp?SF...

Also, Psittacosis is an accepted hazard to human health and should be taken into account during the risk assessment process.

I would also add dependant on how long this has been going on in terms of pigeon entry into an area (if indeed this is internal).

Don't forget the possibility of dead little birdies as well including maggots, decomposing birds etc