Are you able to provide a video of the one that’s having trouble walking and the one inhaling? While Mareks Disease is common, there are also other reasons why your bird is experiencing these symptoms. To me, both seem to be having unrelated issues to one another. How old are they? Do they lay?
1) Vitamin B-12 deficiency- Vitamin deficiencies in chickens are common when they’re not on the correct diet to supplement their body. Vitamin deficiencies can come out similar to Mareks Disease- having trouble walking, weak or wobbly legs, limping like walk or unable to walk.
2) Egg bound/Egg broke inside her- Sometimes chickens can become egg bound or have an egg break inside their bodies and this can cause them to be unable to walk.
3) Botulism- Botulism can cause similar symptoms to MD as well, especially since it’s a toxin. It makes birds unable to walk, stand, have seizures, tremors, hard time walking and sometimes paralysis of the legs and other body parts. Botulism is usually deadly and acts pretty fast.
4) Bumblefoot- Bumblefoot is a staph infection of the foot, it is caused by an injury somewhere on the foot, letting bacteria into the body, causing infection. Check the bottom on her feet and see if you see anything. Pus builds up and hardens, causing pain, which then can cause limping. You’d have to remove the kernel and treat.
If it is none of the causes I’ve listed above, you could potentially be dealing with MD.
As for the other hen, you could be dealing with a respiratory disease, but I can’t say unless you can provide a video and more symptoms.
