Straight to the mouth.
I would get the paste if I were you.
You can even squirt it on a small piece of bread (I would never advise feeding bread except for this way) and feed each bird separately...if you are worried about squirting it in to their mouths.
Just take one out of the coop at a...
Great then you will be able to buy the Safe-Guard goat liquid or horse paste at your nearest farm supply store.
How many birds do you have total?
If just a couple one tube or horse paste will work.
If more than just a few get the goat liquid.