Yes you could "try" switching mates, but i doubt that will fix your issues. I know a little about breeding DYHs and they are one of the more difficult of the amazons to breed. I have tons of questions and many other things to try before you switch mates. Have you successfully bred other amazons? I mean , do you know what your doing? Typically you should not have DYHs within eyesight of other zons , especially other DYHs or any of the Yellow Front subspecies. You might get away with OWAs,BFAs, etc but not other related subspecies. I quess one of the biggest question is how old are they, how long they been together? WOW, there's so many things that matter when breeding DYHs. Don't be too quick to change things up yet. They take time. How about some more history if you really want help.