I cannot see any typical scabs of fowl pox in the photos, but the eye looks like a respiratory disease such as mycoplasma (MG) or coryza. Does she smell bad? That can be a sign of coryza. With so many sick, your existing flock will eventually become carriers if you introduce these birds. The sick one inside the house may already be exposed if they are near each other. Hand washing and keeping these chickens apart is very important.
I would want to get some testing to see what disease I was dealing with. You can get a PCR test for both MG and coryza if you contact a poultry lab that does this from a swab. You can sacrifice one, and also get a sick bird tested during a necropsy (autopsy) by your state vet. MG is fairly common in backyard flocks, but coryza is a more serious disease. Thick foul smelling nasal mucus, pus in eyes, coughing, wheezing, and rales may be common. The pus needs to be removed from the eye, and it can be thick and hard to get out without squeezing and probing. Antibiotic ointment such as Terramycin ointment can be used twice a day after pus is removed.
MG symptoms may improve with Tylan 50 injectable given orally, but it won’t cure them or make them not be carriers. Dosage is 0.25 ml per pound 3 times a day orally, for 5 days.
If you have fowl pox going around, it can weaken the chicks, so pay attention to how much they are eating and drinking. Do not disturb scabs, since that can spread the disease, and fallen scabs are infectious to others.