Is my thawed chicken still good 4 days later in the fridge?
It's impossible to answer this for sure, it depends on how fresh they were when they were frozen and other factors. If they were frozen quickly after you bought them and they were well within their sell by date they are probably still good. 

The easiest way to tell is to smell them, your nose is the best detector you have. If they smell bad get rid of them. If they smell okay feel them, if they are super slimy it's not a good sign, although they still may be edible (wash them in cold water first). A bit of sliminess is perfectly normal.