Any ideas what would cause this in a 5 month old black australorp, I noticed her limping so I took a closer look and found this along her leg/lower abdomen, missing feathers and this big crusty scab , I couldn't find any signs of mites/lice
Have you ever noticed her lying down a lot or sitting on the roost during the days when everyone else is out running around? The crusty scab could be a breast blister that has broken and scabbed over. Breast blisters are common in birds who lie down a lot because of disease, or leg or foot pain. Has there ever been any respiratory disease in the flock, even mild symptoms or other chickens that were lame? Some causes of lameness are mycoplasma synoviae (where breast blisters are common,)viral arthritis or tenosynovitis, or a leg sprain. Mareks disease can also cause lameness and there is a type that also can cause skin lesions. Does she hold her leg up, or does she drag the leg? Is there any swelling of the foot, leg, or joints? I would cage her with food and water for at least a week to rest the leg. Here are a few links to read about those diseases, and below that is an excerpt from Merck Manual: http://www.thepoultrysite.com/diseaseinfo/99/mycoplasma-synoviae-infection-ms-infectious-synovitis http://www.thepoultrysite.com/diseaseinfo/164/viral-arthritis http://extension.unh.edu/resources/files/Resource000791_Rep813.pdf
Clinical Signs and Lesions of mycoplasma synoviae
Although slight rales may be present in birds with M synoviae respiratory infection, usually no signs are noticed. Birds under stress or with concurrent infections are more likely to be clinically affected. The first signs of infectious synovitis include pale-bluish head parts and lameness in many birds with a tendency to sit. The more severely affected birds are depressed and found resting around feeders and waterers. Hocks and footpads are swollen, and sternal bursitis (breast blisters) may be seen. Morbidity is usually low to moderate with mortality of 1%–10%. Effects on egg production are usually not apparent, but instances of transient egg production drops have occurred in layer flocks.
Respiratory lesions may be absent, or consist of mild mucoid tracheitis or sinusitis with airsacculitis when birds are stressed from poor air quality or challenged with Newcastle disease or infectious bronchitis. Early in infectious synovitis, a creamy to viscous yellow-gray exudate is present in most synovial structures but most commonly seen in swollen hock and wing joints. In chronic cases, this exudate may become inspissated; livers are enlarged and sometimes green, spleens are enlarged, kidneys are enlarged and pale, and birds may be weak and thin with breast blisters from sternal recombency.
She has been laying in the coop more than normal and her leg actually seems to be a bit better but she was holding it straight up and putting some weight on it never just dragging it around. One friend is insistent it's mites but I haven't found any signs of them even inspecting the coop at night with a flashlight
Oh that's so good I'm glad she's feeling better. How did you treat the scab? Also did you give her any antibiotics? We are getting the vet to check mine out in case of MS (to give her some baytril, on the recommendation of the Backyard Chickens community).