Newbie here please help me..
At 4wks old are they still in a brooder with heat?
What type of food are you normally feeding?
You mention that they are sneezing - any coughing, discharge from eyes or nose?
Mealworms make a fine treat, but should not exceed more than 10% of daily intake. Growing chicks need to eat a main ration of chick starter to ensure they have the proper amount of protein, vitamins, minerals and amino acids.