Broadhead blades can be removable, they just cannot be expandable, in otherwords the blades can not have a pivoting point that allows the blades to pivot upon entering the animal.
Also the following rules apply to broadheads when archery hunting:
With arrows or bolts having broadheads measuring less than seven-eighths (7/8) inch in width and having a primary cutting edge less than fifteenth-thousandths (0.015) inch thick.
With arrows or bolts having expanding broadheads
With arrows or bolts having barbed broadheads. A barbed broadhead is a broadhead which has any portion of the rear edge of the broadhead forming an angle less than ninety (90) degrees with the shaft or ferrule.