What kind of feed? If anything other than chick feed do they have grit? Sorry lots of questions but if we figure out what is causing the issue the easier to help.
For now do what your doing. Yes drop liquids on the tip of beak. It should swallow it. That's safer than trying to put it...
Electrolytes.. even Gatorade..
how big is your brooder? How many chicks are in there? Can they get away from the heat? What type of bedding are you using?