They are fed layer crumbles with mixed birdseed with worms for treats and I will give them bananas with powdered vitamins, crushed eggshells, various fruit and vegetable scraps as treats.
Do you mix the birdseed with the layer feed or is that given separately?Their coop is I believe a 4x6 with 4 nesting boxes and the entire bottom is run. I also hang a cabbage to prevent boredom.
I would cut back on the treats a bit and increase protein.
While they may have done well up until now in the coop/run, when birds are molting they can be quite touchy/cranky and sensitive. Essentially, they are getting on each others nerves. Letting them out more may help with the picking problems, but long term, if possible, add more run space to help relieve tensions.
There are no hard and fast rules for coop/run dimensions, but for large fowl a good "guideline" is to provide 4 sq ft of coop space per chicken and 10 sq ft of run space per chicken. Some get along with less while others need much more room.