I have a backhoe that is not maintained and slowly loses height over time. I can see the signs of hydraulic fluid leaks. I am wondering if this sagging issue is the result of the leakage?
Yep, that sagging is most likely from low hydraulic fluid - leaks will definitely cause that over time. Check the hydraulic reservoir dipstick or sight glass (depending on your model) with the boom and bucket lowered and the machine on level ground.
Yes, the sagging is likely due to hydraulic fluid leaks, low fluid levels can cause loss of pressure and poor performance. It's best to get the system inspected and repaired soon to avoid further damage.