Hi Pam,
I don't think you can use corid and tylan at the same time. With the symptoms they have, I would tend to think it is either cocci or respiratory infection of some sort, but it really could be something else entirely.
I don't think it would be a crop issue, since that is not contagious. But some sicknesses do slow down their little systems and that could result in crop problems.....but, there would have to be some other underlying cause.
Did I ask you already if they have free choice access to grit?
Here's where I hesitate to give any solid advice due to my lack of experience; you have already given them a penicillin shot, and then there's the possibility of giving them either tylan or corrid, depending on which you
think is more likely the problem, cocci or respiratory. I don't know how an already compromised immune system will react to having penicillin and then another type of Med. I guess at this point you have nothing to loose, I just hate playing with antibiotics without knowing for certain that you are using the right medicine for the problem. Its terribly frustrating.
No matter what course of meds you choose to use, replenish their systems with probiotics. Since yogurt contradicts some antibiotics, I would pick up probios powder at your feed store and mix it in with a wet
treat daily. They depend so muvh on good bavteria for digestion, and the antibiotics will wipe it out. If you treat with corid in their water, I would give them drops of nutri drench directly in their beaks. If you end up using tylan injectable, then you can put the nutri drench in their
water.
Ok, for tylan 50 injectable 1/2 CC for three days only,
in the breast muscle, changing places each day. For the corid, it's 1 teaspoon per gallon of water, changed daily, for 5 days. This dosage is for the 9.6% liquid corid.
Is there any way you can get one of the sick ones to a vet first, to find out for sure what it is?
Please keep us updated, you're doing everything you can!