No you don't have to give them something the first few days other than food and water, I never do. Broody hens never do. Some people on here like to give various things, especially in the water, but many of us don't. Or maybe they were talking about some vaccine, but again many or most of us don't do that either. Some of those things won't hurt and might help, but chicks are not going to die en masse without them.
You say they act funny. Can you describe how they act? Is it all of them or a few?
How are you brooding them? What does your brooder look like? How are you providing supplemental heat? What are you feeding them or giving them to drink?
It sounds like you may have hatched tiny pullet eggs, the first ones the pullets lay. It's generally recommended that you do't do that, give them some time for the eggs to get bigger before you hatch them. Plus the eggs are pretty complicated to put together in the pullet's internal egg making factory. Sometimes it takes a few days for them to work out all the kinks. If the egg is not right them the egg may not hatch or the chick may not make it. I hatch pullet eggs a lot, though I generally wait until the pullet has laid about a month before I incubate eggs. The eggs will hatch, but the hatch rate is usually not quite as good as regular eggs. If the eggs hatch practically all of them live, but occasionally I might get one death. If it is one or two of them then this might have something to do with it, but if it is all or most, this is not your problem.
How are you heating them? The chicks are pretty tough when it comes to temperature but there is a range they need, especially for the first few days. Either too hot or too cold can be a problem, but their behavior will tell you if this is the problem. The ideal brooder is one where you have a warm enough spot for them to go to when they need to warm up but also a cooler spot they can go to if they get hot. A cold breeze can also chill them, so they need some protection against a cold breeze, like an AC vent.
Most of the time when this type of thing happens there is some kind of poisoning involved. It might be poisoned food, poisoned water, or fumes from something. I have no idea how you are doing any of these or where they are but you might think about this.
