I dont know what causes stunt growth but I would give them some vitamins but make sure she is getting high protein feed. If you are giving treat give them at night just to make sure she is eating the feed more than the treats. Maybe you could try giving her some organic plain yogurt mixed with the crumbles for protein and pro biotic boost.
She might have fought an illness, that was not visible to you. Or she might have had a difficult hatch, or a bad incubation period. So many things could affect her ability to thrive, including the health & condition of her mother hen, the hen that laid the egg from which your girl hatched.
Give her a little extra high-quality protein each day. Along with vitamins as mentioned. I had one chick that grew very slowly, even though she was the largest baby chick, she soon was outsized by the others. When I realized what was happening, I hand-fed her nearly every day for a couple months, to make sure she was getting high quality nutrition for growth. Most days she got a grated hard-cooked egg, or a small amount of steamed fish scraps, or some pieces of high-quality dry cat food or a handful of sunflower seeds. She's doing okay now, and she lays 2 eggs, every 3 days. Still she's the lowest on the pecking order and pretty much afraid of most of the flock, except for her one buddy. I've long since stopped her individual feedings, but every now & then I'll sneak her a special protein treat, just in case she's having trouble getting her fair share.
Thanks yaw. I appreciate the idea's. I'm assuming the yogurt should be flavor free or does it matter? Is there a limit to how much yogurt I should give? I will get a photograph when I feed her some high protein so you can see what I'm talking about. I'm really worried about her & as I looked at the 2nd BO who came from the same batch, she looks a bit smaller too.
I have 3 barred rock hens purchased at 3 weeks, 4 weeks and 5 weeks old (approx). The 4 and 5 week old girls are doing great they seem to be growing at a normal rate. My then 3 week old girl hasn't budged she is as small now as when I got her. She is fully feathered but peeps, peeps, peeps all the time and she doesn't open her eyes all the way.
We called the woman to bring her back but I couldn't do it. My problem is I have to integrate everyone with the older hen and when I try she immediately goes after Patty. I don't want to leave her by herself while everyone else lives together, waiting for her to grow, it's a tough call.
I told my DH I wanted to make her a house chicken, OH YEAH, that went over well. Other than her size and her eyes and being stepped on by everyone she seems to be healthy and happy. Not sure if she will ever be able to free range either.
One idea would be to put one of your least aggressive chicks with your tiny one, while it grows out. The tiny one will do much better with its eating and drinking, if it has a chick buddy that's doing the same thing. Chickens like to play "follow the leader". And it's best for cuddling up at night, especially for a tiny one that may need more warmth. Once it grows and you're ready to introduce it, there will be two going in, which is SO much better than one.
ETA: I guess I didn't read well...she's feathered out. So, maybe give her 3 drops of polyvisol vitamins every day. she may have some vitamin deficiencies which can be common. also, you might try using a red light in the coop, to help with the introduction of the new chicks with the older hen. red light makes it harder for them to see the "victim".
Now named "Dot" for obvious reasons, my orp is STILL tiny BUT more energic. Off all things one can miss, I missed the most important one ~> "Dot" is stand offish, will not eat with other chickens and stays to herself chic.
One of my water feeders is leaking so I bought another one. While there I decided to buy another feed because I am lazy & do not want to have to keep filling up the feeders each day if I don't have too.
Once the feeders were all filled & inside the coop all the chickesn (Except Dot) ran to the feeder. Dot went to the one no one was at. A few seconds later one of the chickens caught wind of this & went where Dot was. The rest of the chickens followed, Dot left & went to the empty one. Back & forth ... over & over again. Now I know what is wrong with my Dot.
In one week I have noticed a huge difference with her. For one, she is getting up in the thick of it all with the other chickens. She doesn't stay long but it's still a step forward & I'm making sure she gets extra special treats from me. Yogurt, blackberries, canalope, etc. She won't fight amongst the other birds & I suspect because she is now so under developed her egg production will not be up to par but that's fine ... she can be my 1st pet only chicken. She is a sweety, that is for sure. : )