YOU SAID:

I have to go hit the hay

INTO JAPANESE

私は干し草を打ちに行かなければなりません

BACK INTO ENGLISH

i have to go beat the hay

INTO JAPANESE

私は干し草を打ち負かす必要があります

BACK INTO ENGLISH

i need to beat the hay

INTO JAPANESE

私は干し草を打つ必要があります

BACK INTO ENGLISH

i need to hit the hay

INTO JAPANESE

私は干し草を打つ必要があります

BACK INTO ENGLISH

i need to hit the hay