hi marcot try taking her out on her own do a couple of retrieves with a tennis ball in the open then let her see you throw the ball just inside a thin hedge and let her retrieve it do this a couple of times then try hiding a couple of balls or dummies down the same hedge without her seeing you do it then walk her down the hedge gentley encouraging her to work in front of you hopefully she will wind the dummies etc and enter the hedge to retrieve them once she learns the hedge contains something exciting for her she should start working them be patient all the best let us know how you get on
Some hawks especially harris hawks never adjust to dogs, they should be introduced during their training/manning stage
she is 4 yrs old and could be set in her ways
Baz