Abnormal pastured chickens, is this Mareks or lack of grit?

[AGRowles]

I run broiler chicken tractors all summer and my third and final batch this season have been abnormal in 2 ways.
1. A few weeks ago 1 bird wouldn't stand up, and perished within 3 days. I would have to pick her up when moving the tractor, I would feed her a little before putting her back in and set her in a corner. Now 2 more birds are not standing and the same thing is happening, I am processing them Monday @ 9 weeks.
**The other birds are still running around abnormally active. Could it be lack of grit, or Mareks disease or something else?

2. Normally they will gorge on feed when its available instead of forage. Normally they like to sit and take persuading to get them to run forward when I'm moving the tractor. Normally I can take them all the way to 7-9 weeks and I lose 1 bird out of 31.
**These birds go through phases where they ignore the food for a couple of days and ONLY want to forage, they also run around like crazy and try to escape and eat grass. Very active and healthy seeming. Any thoughts on why this batch has been different and on the apparent paralysis?

 

[Crazy for Chickens!]

Well, 9 weeks is a little long. You are supposed to process at 7-8 weeks. They are probably getting too large, and dying.

 

[AGRowles]

Well, 9 weeks is a little long. You are supposed to process at 7-8 weeks. They are probably getting too large, and dying.

No that's not the problem but thank you. This happened a few weeks ago in the same batch. All the chickens are running around and even escape the enclosure to run and forage. It's a strange batch which is why I'm taking them to 9 weeks.

 

[Melky]

I run broiler chicken tractors all summer and my third and final batch this season have been abnormal in 2 ways.
1. A few weeks ago 1 bird wouldn't stand up, and perished within 3 days. I would have to pick her up when moving the tractor, I would feed her a little before putting her back in and set her in a corner. Now 2 more birds are not standing and the same thing is happening, I am processing them Monday @ 9 weeks.
**The other birds are still running around abnormally active. Could it be lack of grit, or Mareks disease or something else?

2. Normally they will gorge on feed when its available instead of forage. Normally they like to sit and take persuading to get them to run forward when I'm moving the tractor. Normally I can take them all the way to 7-9 weeks and I lose 1 bird out of 31.
**These birds go through phases where they ignore the food for a couple of days and ONLY want to forage, they also run around like crazy and try to escape and eat grass. Very active and healthy seeming. Any thoughts on why this batch has been different and on the apparent paralysis?

If they seem unable to stand or want to walk typically it is Mareks but to be sure you need a necropsy when one passes to verify. I would still offer them chick grit prior to 8 weeks and poultry grit after 8 weeks. Lack of grit usually results in swollen, impacted, and or sour crop not lethargy then quick death.

 

[AGRowles]

The "paralysis" is overnight, not progressive as I've read. Also of the 3 affected birds, all between 4-8 weeks old in the same batch, it has only affected the legs, never the neck or the wings. Moreover, none of my free range egg layers seem to have any issues and it would affect the entire flock I read. I REALLY hope it's not Mareks.

 

[Wyorp Rock]

You are moving them to a new section of ground each day, but this is ground that previous birds have been on correct?

It could be Marek's, but I would be inclined to treat for Coccidiosis. A fecal float would confirm an overload - do you have a vet that will do the test for you?
If a test is not possible, you can treat them with Corid (amprolium). This is found at most feed stores in the cattle section.

Corid dosage is 1 1/2 teaspoons Corid powder or 2 teaspoons of 9.6% Corid liquid per gallon of water. Give for 5-7 days - make sure this is the ONLY water available during that time period. Mix a fresh batch at least once a day.
There is no egg or meat withdrawal with Amprolium.

If you happen to lose more and the Corid does not work - the only way to know for sure the cause of death would be to refrigerate the body and send it to your state lab. Your lab is at Cornell you can find more info here https://ahdc.vet.cornell.edu/

 

[Greganderson]

I run broiler chicken tractors all summer and my third and final batch this season have been abnormal in 2 ways.
1. A few weeks ago 1 bird wouldn't stand up, and perished within 3 days. I would have to pick her up when moving the tractor, I would feed her a little before putting her back in and set her in a corner. Now 2 more birds are not standing and the same thing is happening, I am processing them Monday @ 9 weeks.
**The other birds are still running around abnormally active. Could it be lack of grit, or Mareks disease or something else?

2. Normally they will gorge on feed when its available instead of forage. Normally they like to sit and take persuading to get them to run forward when I'm moving the tractor. Normally I can take them all the way to 7-9 weeks and I lose 1 bird out of 31.
**These birds go through phases where they ignore the food for a couple of days and ONLY want to forage, they also run around like crazy and try to escape and eat grass. Very active and healthy seeming. Any thoughts on why this batch has been different and on the apparent paralysis?

If your running Cornish X you are probably feeding to high protein
Drop your protein back to 19-20%
If you are then pull the feed
To big to fast a regular problem for Cornish X

 

[Greganderson]

I also agree with crazy 4 chicken
9 weeks is long especially for males
Remember Cornish X were not designed to live that long and industry doesn’t need them to walk

 

[AGRowles]

You are moving them to a new section of ground each day, but this is ground that previous birds have been on correct?

It could be Marek's, but I would be inclined to treat for Coccidiosis. A fecal float would confirm an overload - do you have a vet that will do the test for you?
If a test is not possible, you can treat them with Corid (amprolium). This is found at most feed stores in the cattle section.

Corid dosage is 1 1/2 teaspoons Corid powder or 2 teaspoons of 9.6% Corid liquid per gallon of water. Give for 5-7 days - make sure this is the ONLY water available during that time period. Mix a fresh batch at least once a day.
There is no egg or meat withdrawal with Amprolium.

If you happen to lose more and the Corid does not work - the only way to know for sure the cause of death would be to refrigerate the body and send it to your state lab. Your lab is at Cornell you can find more info here https://ahdc.vet.cornell.edu/

For the most part only the egg layers have lightly tread the area where the broilers are. I do not have a vet that I know of for chickens, but might send one to cornell. There is no bloody stool to be seen, and again no other signs of Mareks in the flock. Hoping this is just a random Cornish thing and isolated to this batch.