How do peas react to hail, anybody have experience with this? Stems are partially broken off.

In your photo where the stem is damaged it will remain a wilted access point for disease throughout the season. The pea plant will continue to grow above that point as a relatively normal plant but it will not stand, plants will grow tilted and laid out. I wouldn’t put the money into fungicide as the peas will not stand regardless. It will still produce a crop but tune up the flex header