i believe a 1 1/2 year old spike could possibly be a 4 1/2 year old bruiser.

That' s my opinion. I seriously doubt every spike will be a scrub...but I guarentee that every spike won' t be a monster either. I' m sure you could take a young spike, put him in a good food plot management area, and with the right nutrients and no harsh weather(winter) on him...he could be a bruiser at age 4 or 5 1/2.