Strange feathers

[rebrascora]

He will eat grit when he needs it. They only need a very small amount and he may be getting it from the dirt/ground. The grit is retained in the gizzard until it is broken down itself to small particles and is then pooped out. They instinctively know when they need more. Cutting back on treats is a good plan as it can cause a lot more serious health problems than just feather damage.

 

[Wyorp Rock]

Sorry I should have said, it is not coloured lines but more like holes. The lines in the photo are where the sunlight is coming through the feathers.
His health seems generally fine but he does get a lot of treats since he is spoiled rotten and dislikes the pellet feed. He lives in the house (long story) and I always worry his nutrition isn't right.

Thank you everyone. I was suspicious it was caused by nutrition. I don't think it is mites and he sleeps according to sunrise and sunset pls gets regular sunshine. I will have to cut down on his treats and hopefully he will eat more of his pellets if he is hungry enough. I have also ordered some poultry vitamin tonic to give him.

Another thing is he doesn't get enough grit. He has access to a bowl of mixed grit all day every day next to his food bowl but never touches it. With the human food he keeps getting I know he needs grit for proper digestion. But how can I get him to eat some?

Is he the only chicken you have?
Cut back on his treats, but if he still doesn't like the pelleted feed, try some chick starter or an all flock type feed.

 

[Shadrach]

Could possibly be feather mites.

It could, but the regulat orientaion of the bars would be unusual for feather mites.

 

[007Sean]

It could, but the regulat orientaion of the bars would be unusual for feather mites.

I thought the same thing but as Shadrach pointed out the pattern is too regular.

 

[townchicks]

It could, but the regulat orientaion of the bars would be unusual for feather mites.

That's the thing, to me, it seems too irregular to be nutritional. Just my opinion, I've never seen a nutritional deficiency that causes holes in feathers. I would think it more likely to cause them to grow out stunted, or malformed. But I'm just guessing, certainly no expert. I have seen feather mites, and that's what it looks like to me, except the bars are rather wider than usual.But that could be breakage due to the damage from the mites, I suppose. Just throwing it out there.

 

[coach723]

This has made me determined to find something on this, I haven't been able to find an image that compares. I did find an article on 'fault bars' in feathers, which from the description sounds like this may be the issue. From my quick scan (very quick) it seems that there are many factors, but physiological stress seems to play a part, perhaps a large part. So perhaps something happened during feather formation during molt. We never asked, but how old is he?
Here is what I found, for those interested:
https://www.researchgate.net/public...ical_and_evolutionary_causes_and_consequences

 

[townchicks]

Thanks, coach, that makes sense. Now, though, I am worrying about my girl Harper, who is in the middle of a heavy molt. Lots of pinfeathers everywhere. I picked her up last night to look at her feet, and scared the crap out of her. I hope she doesn't get stress bars.

 

[Shadrach]

Here they are called stress or fault bars. In the UK they call them fret bars.
Victoria Roberts BVSc MRCVS; Diseases Of Free Range Poultry.
“Stress bars or fret marks will appear on growing feathers following a nutritional crisis (lack of food, bad weather, bullying) but at next moult will disappear if no further insult.”
Here in Catalonia where free ranging can often mean no supplementary feed such bars are quite common. The bad weather part of the above quote does of course determine the chickens ability to forage successfully. Given the situation the OP describes for this fowl, bullying seems unlikely. However, the OP indicates the chicken is ‘spoiled’ with treats and I have assumed generally bad diet.
Feather mite is rare in chickens and normally effects wild birds. Feather mite is of the red mite species and if present will be found where blood is flowing through the feather. It doesn’t live on the fowl.
I can’t find any pictures of feather mite damage atm but it doesn’t look like the pic in the OP.

 

[SBFChickenGirl]

But how can I get him to eat some?

I just give a handful of grit on the food. They pick through it with they want it, and they eat it if they do.

 

[coach723]

So that looks like the 'cause', but without a definitive answer to this specific bird.
Here's another article with a picture. https://www.windycityparrot.com/blog/2012/08/23/feather-stress-bars-bird/
And doing a search for fret bars found this image: