Please please help me

My hen is really ill. Ive had her and one other for almost a year now but over the last few days she grown ill. She lays down all the time and cannot walk, when I pick her up and try to see if she will take a step her feet curl and she wont put the down, I tried opening the and putting her on the ground but she flops to the floor, her right leg slides outwards and her wings are floppy too, especially her right wing. She’s barely eating but I have her drinking a fair bit. I have removed her from the pen and have her in a basket in the kitchen and she hasn’t moved all day! I quickly examined her and found a single mite around her leg and a few lice around her body. I didn’t have a good look but plan to. Im afraid she will die! She’s been like this two days but not as serious, she was still able to walk just a bit limp. She was worse this morning but by this evening she had been trying to lift herself with no luck!
Are the lice the problem? Does anybody know a cure? Or a diagnosis?