Why my chickens losing their feather

[lamanash]

I'm thinking it's feather picking then. Have you seen any of that going on? If not, and you have some time to watch the behavior of your flock, see what they do throughout the day.

What does your set up look like? Do the birds free range or are they kept in a run and if so, how big is it (and how many birds) and is there any clutter or boredom busters inside?

Also what are you feeding them? Feed protein %? Any treats/snacks? Higher protein feed may help with feather picking issues, and with regrowth of feathers.

They are free range and it’s plenty of space there, I give them chicken food and provide 4 sticks of apples. Tomato, cucumber, broccoli every day. They have swings and some chicken toys. Also I give them cabbage or lettuce in the mesh hanger

 

[lamanash]

They are free range and it’s plenty of space there, I give them chicken food and provide 4 sticks of apples. Tomato, cucumber, broccoli every day. They have swings and some chicken toys. Also I give them cabbage or lettuce in the mesh hanger

What is the best source of protein for chicken?

 

[rosemarythyme]

They are free range and it’s plenty of space there, I give them chicken food and provide 4 sticks of apples. Tomato, cucumber, broccoli every day. They have swings and some chicken toys. Also I give them cabbage or lettuce in the mesh hanger

Free ranging is fine (as they can find bugs and worms to their liking) but that's a lot of extra vegetables, which is likely diluting down the protein in their feed. You didn't specify what your protein % is in your feed, but most chicken feeds are between 16-20% protein. So if you're feeding the lowest number, 16%, you're diluting down their protein intake below what's considered the minimum for good laying and overall health.

What is the best source of protein for chicken?

Live insects, probably? Some folks grow mealworms or BSFL at home.

If you cook meat or fish, you can give them anything you're discarding. If you don't have much of that, some folks supplement with a little dry cat food (high in sodium so use in moderation), unsalted tinned fish, fish food...