Noticed over the past couple of days, one of our buff orpingtons has not been her self. She is around 18 weeks old now, and in with a flock of 7 other birds ranging from 18 weeks to 24 weeks. They all get on fine, and been together for some time, Running free range on grass. Recently treating our whole flock with tylan, Due to a cold in a couple of the chickens that simply would not shift. This has now cleared up 99%, The chicken in question didnt suffer with the cold and was active until we stopped giving them the antibiotic. On our Clean out, We did find a small amount of redmite, Though this was treated and seems to have cleared up/clearing up. No signs of mites from daily cleaning, DE and Mite powder. We have just bought her into the house where it is a little warmer for her and out of the wind. There are no signs signs of Lice/Mites on her as i type this. She does want to eat, but will only eat a very small amount, and will only eat if we mix the food down to a paste. (Equivalant of at the most 6 - 7 grains of wheat a day) We have seen her drink, but now monitoring this more with her in the house. We havent seen her poop, as pretty hard to see this within the paddock, Again will see if she does in the house, but i doubt it with lack of food. Her Crop feels Empty. (no Food and No Fluid) My partner checked for Impacted crop, and said she doesnt think this is the case. She does sit around, and just wants to sleep. She does have a small groom of her self, and has her tail down. She is at times quite alert, She does run around with the other chickens but soon stops and sleeps where ever she stops. She did have a good dust bath 4 days ago but not as crazy as the others (as if she didnt have the energy) She is feeling a little under weight, can feel her bones quite clearly. She is currently sat with us, but has her head tucked down and balled up, Standing up. She has been wormed about 5 weeks ago. She is currently having a Malt, Got quite a lot of new feathers growing, (same with some of the other buffs in the coop/Run which are not having the same other symptoms Any advice would be great, Hope i havent missed anything on here and if i have, Just ask and il reply asap.