My silkies eye
Mycoplasma (MG) can cause foam or eye drainage that crusts, but she could just have an eye infection. Since you have been treating it for a week, I would get some Tylan 50 injectable from the cattle section of your feed store. Give her 1/4 ml ORALLY twice a day for 5 days. You will need a 20 gauge needle and some syringes to get it from the vial. Is she eating and drinking okay? Have you added any new chickens recently? Does she have a bad odor that could be a sign of coryza? Eye infections may be from respiratory diseases, but also can occur from poor ventilation, dusty food or conditions, as well as ammonia odors in the coop from droppings. Here is a link about MG:
Synonyms: MG, chronic respiratory disease (CRD), infectious sinusitis, mycoplasmosis
Species affected: chickens, turkeys, pigeons, ducks, peafowl, and passerine birds.
Clinical signs: Clinical symptoms vary slightly between species. Infected adult chickens may show no outward signs if infection is uncomplicated. However, sticky, serous exudate from nostrils, foamy exudate in eyes, and swollen sinuses can occur, especially in broilers. The air sacs may become infected. Infected birds can develop respiratory rales and sneeze. Affected birds are often stunted and unthrifty (see Table 1).
There are two forms of this disease in the turkey. With the "upper form" the birds have watery eyes and nostrils, the infraorbitals (just below the eye) become swollen, and the exudate becomes caseous and firm. The birds have respiratory rales and show unthriftiness.
With the "lower form", infected turkeys develop airsacculitis. As with chickens, birds can show no outward signs if the infection is uncomplicated. Thus, the condition may go unnoticed until the birds are slaughtered and the typical legions are seen. Birds with airsacculitis are condemned.
MG in chicken embryos can cause dwarfing, airsacculitis, and death.
Transmission: MG can be spread to offspring through the egg. Most commercial breeding flocks, however, are MG-free. Introduction of infected replacement birds can introduce the disease to MG-negative flocks. MG can also be spread by using MG-contaminated equipment.
Treatment: Outbreaks of MG can be controlled with the use of antibiotics. Erythromycin, tylosin, spectinomycin, and lincomycin all exhibit anti-mycoplasma activity and have given good results. Administration of most of these antibiotics can be by feed, water or injection. These are effective in reducing clinical disease. However, birds remain carriers for life.
Prevention: Eradication is the best control of mycoplasma disease. The National Poultry Improvement Plan monitors all participating chicken and turkey breeder flocks.