Okay here is the original thread which started out as a breed check over here: https://www.backyardchickens.com/t/938227/i-was-told-this-was-a-light-sussex-true-just-wrong-age The consensus seems to be she is a light sussex but something is definitely wrong with her and not just a younger age. Please read the previous thread for a more complete history of where she came from because it is very relevant. I also obtained another picture of her today which more accurately reflects how she composes herself - which is very different to the other chickens Symptoms that could point to illness include: 1. she isnt growing, shes been looking like this from age 16 to 23 weeks despite getting special feeding attention and eating with an enormous appetite. 2. she has greyish eyes 3. her comb is pale and possibly underdeveloped for her age 4. she looks disheveled in appearance. i have monitored her and she does clean/groom her feathers but doesnt seem to ever get them to a great condition. 5. she sticks her chest out but always tucks her head in like this picture. it makes her appear very compact and squat compared to the other proud perky chickens we have. 6. she arrived with another chicken of the same type and size which died right away (see previous thread) 7. shes a bit of a loner except at night when snuggled under Roxy our 27 week old RIR. Things that seem to be okay: 1. she eats a lot and eats healthily and is one of the first to gain access to food. 2. she jumps around the run easily and goes where she pleases 3. she can support herself with no issues 4. she drinks well Things I have done: When her partner died she was at first separated and kept inside for a bit and monitored closely. She didn't develop any issues with eating, supporting herself or breathing and appeared perky so she was reintroduced. Because she is still so small, I have been giving her extra feed to herself every day including growers, hot oats, mealworms, veg. She eats it well but still isn't growing/putting on weight. All the chickens generally receive cider vinegar in their water and the girls are currently also getting a vitamin boost liquid too to help our ex broody. Their run and hutch is cleaned every day and once a month I Diatom the hutches. In case it is worms, I have started adding Diatom to her feed to help but I only started this today. Alas I cannot afford to take her to a vet at the moment - her sister just cost us a small fortune at the vets.