I hate to keep being the opposing side, but....you can try giving it in the water and they might drink it. Ours drank meds in the water, and didn't seem to notice anything. Don't know about baby vitamins...maybe they can taste those more. Ours are free range, so I don't think they're as picky about the taste of what they drink, as they sometimes drink from puddles. Personally, I think the stress involved with catching them, and etc, just makes things worse for them illness wise...especially if they are not used to being handled, and can't breathe well. We had to catch ours twice six weeks apart (in the dead of winter and in the cold early spring) to administer their ILT vaccine, and stuff to delouse them. We called up a few friends and had a chicken catching party. It was still a rodeo, but made it more fun that way. We caught them over a period of days, and just set up a few holding pens, til we had them all. We are set up same way; couldn't reach them at night. If you are able to catch em, if you can, put at least the worst ones in a small pen while you're treating em. This nightmare will not last...if you persevere, you'll probably come out on top. You might have to spend a few dollars, but it'll be oh so rewarding when you win. Just stay in touch, and we'll all help you. If you want to call the OSU vet clinic in Ohio, there's a poultry expert in the vet school there that'd help you over the phone...let me know if you want his name and number.