Hi. I'm new to raising monarchs. It was an accident really. I saw several and decided to put them in a screened habitat. It's really stressful. A few do not look OK but how do I know for sure? I'm posting photos of one of them. This one never seemed form much of a J before attempting to pupate.

Sometimes they can be sick with bacterial diseases and will die before making it to the butterfly stage.

Check out mrlundscience on YouTube. He has a series of very helpful informational videos, especially for those just getting started raising monarchs.