let me begin by telling you that seeing that many chubs in a trout stream is not a good sign. Chubs is one of the tell tale signs that the stream is warm, trout prefer colder water temps; where chubs do not.
to answer your question, yes you can use chubs in streams that are not category 5: catch and release and artificial only.
If you are on a stream without those special regulations, and the chub is from the same stream, yes you can use them. Make sure you follow though with your trout bible to make sure you are in regulation free waters.
To answer the second part of your question, big browns LOVE chubs. It’s like giving crack to a baby (especially at night).