chickens that can't walk

[msshepherdess]

A dog got a couple of my chickens. There were no external injuries. After a day or so, one of them can't stand up. She eats and drinks, but her legs just stick straight out. The other one's foot is curled up and her walking is getting worse. Today, one that didn't get hurt by the dog is having trouble walking. I can't afford a vet. Is this all connected and not an injury problem? Worms or some disease?
They're comets (cinnamon browns), about 3 months old. They eat laying mash with the old chickens.

 

[DuckLady]

Dogs do a lot of internal damage. They bite and crush internal organs and can crush nerves. And often they leave no external signs.
I am sorry this happened to you.

 

[msshepherdess]

This is getting crazy! Yesterday, one of my chickens just quit walking and today I went out there and she was dead. This was definitely not a dog problem. Any ideas? I'm really concerned about something contagious.

 

[CarriBrown]

Sounds like it could be pest related. You should worm and dust your flock for parasites. Are they underweight when they die?