Not really unheard of for this to happen on an older rig. Depends a lot on how long it's been sitting ever it's life with the jacks extended, whether it's been driven in winter in salt country etc.. These will metal fatigue over time. It is probably pretty unusual for two to go at the same time.
Time for new ones all round I think. The good news is that they're not very expensive, and if they're HWH, they have improved them greatly.
The jacks will likely go down without the springs, but they won't come up and might not stay up if you pushed them up manually.