Checking undercarriage

Trying to get an idea on the shape of the undercarriage on my Deere 225, i've attached a few pictures, the sprocket seems to be fairly worn but everything else seems to be ok to me? Only problem i've noticed is a few bottom rollers are leaking, as the one pictures shows. Is there an easy way to replace the oil to extend their life? View attachment 170634 View attachment 170635 View attachment 170637 View attachment 170638

Checking undercarriage