When they get closer and over 25 their hair starts to get grey and they slow down drastically! They also lose more health with each passing day, than they recover even when full hunger, its at that point you may want to get them and another gobo in the bunk bed to help the next gobo start off with some good stats.
It can also depend on their hunger and their Personality.
Viewing post in Bug Fixing and Walkthrough! comments
I think that speed debuff might be happening a lot sooner than the 25 for some goblins I put a high stat (fresh out of the bunk) into a race and it did fine, but when it reached 5 days old its stats mattered less and less for races. With a high turnaround to age would it be possible to add an option to retire a goblin?
I looked into it and you are right the age was affecting the gobos well sooner than I intended but I asked about the personality mainly because I realized the way that I was doing it also was wrong , SO I wanted to make sure that it was a case of one or the other and it was both.
Next version should fix this, thank you for explaining it and giving more information on it because it helped find the problems.