New mother hen with possible scaly leg mites

Hi all

I noticed today that my hen (with 1 mth old chick) has raised, darker coloured scales on the bottom of her leg, her front ankle part basically. 

What would be the best form of treatment for her, which wont cause any health issues to her or the chick? The chick, from what I can see, has no problems, and neither do my 2 other girls as they have been separated since hen went broody. Dip her legs in oil? Vaseline? It will be a nightmare to treat her as I can barely get near her as she is so protective of chick!

Many thanks in advance

I've found a liberal coat and massage with castor oil to be a great, one time treatment that not only works as a natural insecticide, but also soothes the discomfort and inflammation, while acting as an antibacterial all at the same time. It also has the wonderful effect of speeding the growth of new, healthy scale to replace the affected scales.  Even works on long standing infestation.

Thanks for the advice, will treat her a.s.a.p ... Just hope I do not freak her and chickpea out too much!