So to answer your original question, yes, you need to make a fresh batch each day. Additionally, if you have some that aren't drinking enough you need to figure out how to get more into them. Many people will make a mash using crumbles and medicated water.
-Kathy
If you think you have coccidiosis and are going to treat it, I strongly suggest that you buy something that will allow you to make a fresh batch each day. That's the obvious thing to do, right?
-Kathy
Some people use give the .006% dose for one to two weeks after treatment.
FDA recommendations:
http://www.accessdata.fda.gov/scripts/animaldrugsatfda/details.cfm?dn=013-149
"Chickens
Indications: For the treatment of coccidiosis.
Amount: Administer at the 0.012 percent level in drinking water...
It does sound like too much... the amount of amprolium per liter needed is 254mg, which is:
20% powder is about 1/2 teaspoon
9.6% liquid is 2.65ml.
-Kathy