Im house sitting for my grandparents for the weekend and they have 9 chickens and 2 ducks out in a chicken house. They are normally freerange chickens but are not let out everyday.

I went in the past couple of days to change their water and these little gray bugs are swarming the walls and under where there water bucket is set at.

I read to pick up a chicken and check it but they wont let me near them.

My grandparents dont seem to concerned but its really grossing me out.

If they are lice then how can I kill them without harsh chemicals?