On very hot days, it can happen that birds go into an odd-looking pose, spreading out their wings, beak open and just remaining like that for a bit. It can look concerning, but it does not mean they are sick or injured - they are taking a sunbath. The reason is not entirely clear, and explanations range from plumage care to personal enjoyment. If you want to read more, you could check this article. (Birds also sometimes do something called “anting” where they sit in a spot with lots of ants, also for plumage care, but here, the Blue Jay is sunbathing.)