I have a hen about 7 months old. Her sister passed away about 1 month ago for no reason. I thought she was going through depression. She seemed to stay by herself, head slunk down and sleeping by herself also. I have a flock of 26. 20 hens and 6 roosters. All bantams. I went into the coop last week and found her on her side unable to stand or walk properly. I immediately brought her inside and started helping her eat. She seems to have trouble pecking the food. Like her head falls to the side and she misses what she wanted to get. She won't bend down to get it. I have to hold it right infront of her face inorder for her to eat. I also have to syringe feed her water. I put and electrolyte , probiotic mix in her water. She is healthy otherwise. I have only found a few bugs on her. Not sure if they are live or mites. I'm fairly new to chicken keeping. The oldest in my flock is only 2. Everyone else appears to be healthy as well. If this is Marek's how do I go about vaccinating everyone. I have 2 broody hens now with chicks to be due on about 1 week so I'm kinda in panic mode as to what this problem is.