I still think it is too hot.
I just have one spot that is about 90F, perhaps as high as 95F for just a couple chicks but they still need a cool space available.
Did you hatch the chicks or buy them?
If you bought them as day olds, they are older than 2 days.
They ship when a day old, 2 days in transit and then the time before you purchased them and then you've had them 2 days. That puts them closer to 5 days or more. 98 is way too hot for them, especially if the whole brooder is that temp.
X10 on the Nutri-Drench suggestions.