bald chickens

Acouple of months ago i had a problem with red mite in my hen house . It wasnt found for a couple of weeks when i noticed my birds had lost a number of feathers and a couple had a few bald patches on them . With the chat room help i got rid of the red mite but the birds still have the bald patches will the feathers return in good time ie malt. I am also having problems with broken eggs . Each day i go to pick up my eggs there is always one broken , sometimes eaten sometimes not. I have 16 bids in a pen with 4 nest boxes and  a long run to run about in. Can anybody offrer any advice please ?