Can you pick up some solid coconut oil at the store next time you go? It's so much easier than trying to get liquid oil into a tiny chick. One way to do it that others have tried successfully is to take a tiny piece of bread and soak up a teaspoon of oil with it. Let the chick eat as much of it as it will. I don't like giving bread to chickens but when you have this sort of a problem, well, you have to deal with it.
To ferment feed, fill a container with enough feed for two days. Cover with warm filtered water until it just barely covers the feed. Add a teaspoon of ACV with the sediment to it. Stir. Let it sit in a warm place as if you are raising bread dough. Tomorrow stir it. The next day, it might be ready to feed if it has fluffed up and smells "yeasty". Stir every day.
The first batch takes 48 hours or a bit more. But the following batches will be ready in 24 since you will use a tablespoon of the previous batch to start the next. I use two containers, I make enough to feed out in two days, and I start a new bucket when I start to feed out of the second bucket.
With fermented feed, chicks will need to be fed continuously all day, but when they reach four months, they can get by with two feedings per day. An adult will eat a half a cup to three fourths of a cup per day. You will need to find bowls to feed it from as dry feeders don't work with FF.
I use dog bowls on those raised platforms so the chickens don't tip them over. For babies, I use a cat bowl after they're a few weeks old. Day-olds are fed out of tiny cups they can't climb into and try to take a bath in. If you've ever seen a baby chick standing in their food dish, you'll know what I'm talking about. Trying to clean FF off a downy chick is not anyone's idea of fun.