NH 316 Driven and Idler Sprocket Feeder Drive Removal

Just recently purchased a NH 316 small square baler and found the feeder drive chain very loose. Many of the teeth on both the driven and idler sprockets were chipped or completely broken.
First the cause?? Chain tension never maintained or??
Second the solution?? Remove both sprockets and chain and replace??
How?? Does the panelling above the sprockets need to be removed to access especially the driven sprocket?
Any help would be appreciated.

NH 316 Driven and Idler Sprocket Feeder Drive Removal