Sorry that I haven’t been up to date, and also that she is declining. I would stop the acyclovir since she is not eating well and having runny poops. I would give her more light, and if possible bring her in to be around other birds in a dog crate, or with you while you are around. If she hops out of the crate again from seeing outside or the other birds, let her be for awhile, to enjoy seeing the others, at least for visits. She might perk up enough to eat better. Here is a good link to talk to your state vet or poultry lab to make arrangements for a necropsy (refrigerate in your refrigerator in double plastic garbage bags) and ask for Mareks testing, since they don’t do it routinely:
http://www.metzerfarms.com/PoultryLabs.cfm