Some chicks hatch with something wrong with them, consider it a birth defect. Some are just not meant to make it. Others like that can have initial problems and overcome them, often leading a normal life. Since it is eating and drinking on its own I think you are in a pretty good place. Most of them that aren't going to make it don't make it that long. Maybe in another week you can really relax with that one but I think you are doing OK. I wish you good luck with that one.
Don't be confused when you read different opinions on here. We all have our own opinions. People use different things in the drinking water for new chicks; vinegar (with or without mother), probiotics, electrolytes, even just sugar. Everybody believes what they do is best or they wouldn't do them. I'm in the camp that just keeps the water clean and treats an individual if it needs treating. I don't think any of that hurts the chicks at all as long as you don't overdo it. I just don't see it as a need.
