Nesting blue tit has fleas - treatable?

[Hereward]

I've set up a nest box with built-in camera and we have a blue tit in residence, sitting on one egg so far.

She seems to have fleas (they are visible on the tv image) and is always having a good scratch. It can't be much fun for her.

Is there any way I can get some flea powder in to the nest box without frightening her? I was thinking of sprinkling it on the entrance hole so it gets transferred into the feathers as the parents come and go? Any brand/type of flea powder? I was going to get some that is used for poultry. Is that safe to use?

Any thoughts/advice appreciated...