Chicken lethargic won't move, head down, convulses, happened suddenly

[llegree]

2 more girls are sick

1is really bad lethargic droopy head nearly dead. 1 can not stand and has droopy wings but can hold her head up and flap her wings around some. we are feeding them both ground up garlic and onion juice and water through a syrienge. The one that was sick yesterday is making a come back but hasn't pooped to much. A couple of times but she is able to eat and drink and walk and run and play so I think she will make a come back and recover. Have changed all food and water just don't know what else to do. We raise organically so can't use a lot of chemicals. Any other advice?

Thanks for the link to the website. Very informative.