fillies require less exercise than colts

Question
hello sir. before you answered me that fillies require less exercise when compared to colts. may i know why? you also told me that fillies are troublesome than colts at training.

Answer
hi   fillies are female and most females do not want a lot of training. colts are much more tougher and need to be trained to get some of that energy out of them. once i8n awhile you will find a big filly that needs to be trained like a colt. thanks ED HESS