Jumping with hock injections?

Hock injections are a messy and expensive situation. If she needs them at 6 and that often she is going to break down really early. Hock injection are not a fix, they simply temporarily keep her sound and able to work and yes with time and increased work she will most likely need them more often to be able to keep going. However you can jump her at that height but i do think you may want to look into leasing another horse.