I am one of the *few* that will give lots of drugs at once. I don't use penicillin, but I have used amoxicillin with Corid, metronidazole and Safeguard at the same time. Oddly enough, the last one i did that with had bloody poop similar to your bird's poop, but without the worms. People say that you shouldn't give vitamins with Corid, something about it being a thiamine blocker, but I haven't seen any published data on it, but I do know that some antibiotics should not be given with certain minerals, so you might want to call a pharmacist and ask what the drug interaction for penicillin are.
-Kathy
-Kathy