Lost feathers and scabs on Chicken’s bellies!!!

[KLPhillips]

All six of my ladies have varying degrees of missing belly feathers and scabs. I feel awful that i did not catch this sooner. I check them but never looked at their bellies specifically. The rest of their bodies look good except some combs got a little frostbite this winter. My son was holding one up and i saw its belly. They have a clean coop with a run with sand in it that i clean weekly. Could it be the sand is too rough? I have not let them out as much in our yard since they tear it up really quick and in the last 4 months i was very pregnant and now have a 2 month old and 2.5 year old. I am a new chicken owner and have had them only one year. We have been planning to change things and try to start doing a deep litter bed this summer. Pictures we took today. The black one is the worst and the rest look like the red one. Advice needed. Thank you.

 

[EmmaRainboe]

They are not broody correct?

 

[Sally PB]

What do they roost on? Someone had a similar situation and figured out it was from the birds' keel bone rubbing on whatever it was they roosted on at night.

I don't know if that's what you have going on, but I thought I'd toss it out.

 

[KLPhillips]

The black one in the photo has been spending more time in the nesting box but she doesn’t have a lot of the other signs of broodiness. Shes not aggressive, she is out in the run a lot and comes to eat scraps and if i let them in the yard she follows or is first out. So i dont think she is. The others don’t seem broody at all.
they roost about 4ft of the ground on wooden roosts we built. I will take a look at them tonight and also check for mites tonight. I checked them all really well this afternoon and did not see our notice any mites or other pests but i am new to spotting them.