Introducing new flock to old coop / coccidiosis exposure?

[allpeepedout]

I have a new flock approaching 8 weeks old. They have been on non-medicated feed and housed separately from my old flock. Starting at 2 weeks old, they have been outside in the daytime on grass / some dirt in my yard. They have eaten crumbles spread on bare patches of dirt. However, none of this grass/dirt area was ever foraged by the other flock, but there are plenty of wild birds about.

I have just started housing the chicks, nights only, in my other chicken coop, in cages up on a table.

I have a large covered run (dirt) for the older flock that I planned to partition off so chicks could cohabit, but I am wondering if the chicks have built up sufficient coccidiosis immunity? Should I put them on medicated feed? Or just expose them to the run for a limited time to build up more immunity? Or is it now okay to just put them in the run, since they have had some soil exposure for several weeks?

Today it's raining, and they are stuck in the cages. Would like to get them in part of the covered run.

Thanks for any help. I'm confused on the coccidiosis issue, and maybe should have started them with the medicated feed.

 

[Eggcessive]

If they have been on grass and dirt already, they should be ready for the run. Corid is a good thing to keep if necessary for treament of cocci, especially since feed stores can run out when you may need some. Medicated feed is not necessary, and many birds end up with it while on medicated feed. Some people will give a weak dasage of Corid for 5 days to chicks first going on dirt as a preventative. Here are a couple of good links to read about coccidiosis that include what symptoms, such as being lethargic and puffing up, to look for:
http://www.the-chicken-chick.com/2012/12/coccidiosis-what-backyard-chicken.html
http://www.merckvetmanual.com/mvm/poultry/coccidiosis/overview_of_coccidiosis_in_poultry.html
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex4616

Corid dosage:

The preventative dose (.006%) for Corid Powder is 1/3 teaspoon.
The preventative dose (.006%) for Corid liquid is 1/2 teaspoon.

The moderate outbreak dose (.012%) for Corid Powder is 3/4 teaspoon.
The moderate outbreak dose (.012%) for Corid liquid is 1 teaspoon.

The severe outbreak dose (.024%) for Corid Powder is 1.5 teaspoons
The severe outbreak dose (.024%) for Corid liquid is 2 teaspoon.

 

[allpeepedout]

Thank you for the great info. Yes, I had read also that the medicated feed may not really be necessary or helpful, so that added to my confusion. I did have one pullet who was lethargic and puffy a couple of weeks ago, but she snapped out of it in about 24 hrs. I'll get some Corid and go the preventative route.