Okay, first of all NO VITAMINS or anything else besides the baby bird formula, water, and an Electrolyte drink like Pedialyte if you have it available to you. A Vitamin supplement won't help Cookie, she has some type of infection most-likely, whether in her Gastrointestinal Tract, her Upper Respiratory Tract, etc., either way Vitamins won't do anything but make her worse. This could be a Bacterial Infection, it could be a Fungal/Yeast Infection, but if she still isnt' eating or drinking on her own then it's not good..She is probably feeling better because the formula has re-hydrated her and brought her blood-sugar up, her blood-pressure up, etc., but the problem is that if she does in-fact have an Infection of some sort, it's not just going to go away on it's own, and she'll start to go down-hill again without the proper Antibiotic or Anti-Fungal medication...
****Very, Very, Very Important!!! DO NOT EVER "PUSH/FORCE THE FORMULA DOWN YOUR BIRD'S THROAT" WITH AN EYE-DROPPER OR SYRINGE!!!!! When I read that you did that my heart skipped a beat, because you're going to cause her to develop another totally different infection in her Upper Respiratory System/Lungs!!! You absolutely cannot force formula, water, or anything else down her throat, UNLESS YOU HAVE A SPECIAL "CROP-NEEDLE" THAT YOU CAN ACTUALLY STICK WAY DOWN INTO HER CROP THROUGH THE OPENING ON HER RIGHT SIDE-BACK OF HER THROAT....There's no way that you can get either an Eye-Dropper or an Oral Syringe down into the opening of Crop at the back of the right side of her throat, it's too deep, you need something much longer and shaped correctly to actually "Crop-Feed" or "Tube-Feed" her...So if you're actually shoving an Eye-Dropper or an Oral Syringe down the back of her throat and forcing the formula into the back of her throat, AND THEN SHE VOMITED AFTER YOU DID IT, unfortunately chances are that you forced the formula right down into her lungs!!!
***The first thing that typically happens when you aspirate any liquid or food into a bird's lungs/Trachea instead of their Crop is they gag and then vomit, because their body's reflex/automatic response is to try to push the liquid/food out of their lungs...The problem is that once you aspirate formula or water into her lungs, a Bacterial Infection is going to form inside of her lungs in a matter of a few days (Pneumonia)...So I'm hoping that this didn't happen, but the fact that you've been forcing food into the back of her throat with an Eye-Dropper and she already vomited as a result of it at least once is not a good sign at all...
You need to keep an extremely close eye on her Breathing...If her breathing becomes heavy or labored, if she starts breathing with her mouth open, or if she starts coughing, then she's got Aspiration-Pneumonia, and she needs the correct antibiotic...We'll cross that bridge if we get to it, hopefully we don't, BUT YOU HAVE TO STOP FORCING THE FORMULA DOWN THE BACK OF HER THROAT WITH AN EYE-DROPPER OR SYRINGE IMMEDIATELY!!! Because if you haven't already aspirated her, you eventually will...
If she has no feeding-response at all, then you simply must take your time, and very, very slowly use the eye-dropper or better is an oral-syringe because it's not glass, or a plastic pipette, etc., and you just have to gradually and slowly insert the tip of whatever you're using to feed her into the left-side of her beak (if you are facing her then you're inserting the tip into your right-side looking at her, opposite the side that her Crop-opening is on), and then you're going to angle the tip from the left-side of her beak (her left side if you're facing her, you're right side) OVER her tongue and towards her right-side of the back of her throat (towards your left side if you're facing her), and then you're going to drop little tiny drops of the formual on top of her tongue and towards the back of the right side of her throat (your left side facing her), and let her lick the little drops of formula up, then give her another one, etc., until you see that her crop is filling-up by using your finger to lightly feel it through the skin on her chest...
I know this is pain and it's going to take a lot longer than the way you've been feeding the formula to her, but you don't have a choice if she isn't giving you any feeding response, and even if she is giving you a feeding response you still can't shove an eye-dropper, oral syringe, or anything else down the back of her throat!!! I'm really hoping she hasn't aspirated yet, but chances are that she has, and if you keep forcing formula down into the back of her throat you absolutley will aspirate her...
When you actually "Crop-Feed" or "Tube-Feed" a bird, you actually insert a very long, specially-angled Crop-Needle down into the entrance-hole of her Crop on the back of the right side of her throat, and then way down into the bottom of their Crop, until you can move the Crop-Needle around and actually see it/feel it moving around way down inside their Crop, under the skin on their Chest. This is the ONLY way to ensure that all of the formula is injected/pushed into the Crop and not down into her lungs. And if you don't have a Crop-Needle you can't do this, as an eye-dropper, oral syringe, etc. aren't nearly long enough, you wouldn't even be able to bet the tip of an eye-dropper into the Crop-hole at the back of the throat...So you just need to make sure you're going extremely slowly and not putting anything into the back of her throat, no water, no formual, not anything...
***Can you open her beak up and smell her mouth, and tell me what her mouth/breath smells like? This sometimes help to diagnose the type of infection the bird has Bacterial, Fungal, or both), and also whether it's in their GI Tract/Crop or in their Upper Respiratory Tract, etc....So it might smell like rotten/rotting food, it might smell like very "sour", etc. Or it might not smell like anything, which typically puts the infection lower in the GI Tract than the Crop, or not in the GI Tract at all...
***Also, what have her droppings looked like throughout this, specifically what were they like when you first noticed that she was sick and had vomited? What color (green, yellow, brown, black, etc.), are they loose or really runny, have they had any bubbles in them, etc.
