7 month old boxer pup being picky all of sudden

Question
I HAVE A FEMALE SPAYED BRINDLE BOXER  WHO JUST TURN 7 MONTHS WELL YOU SEE SHE JUST RECENTLY STARTED BEING PICKY  ABOUT HER FOOD. IT HAPPENEDS IN THE MORING AND IN THE EVENING. WHEN I WAS TRYING THIS NEW FOOD THAT I GOT A SAMPLE OF SHE LOVED IT AND SO I BOUGHT A 6 POUND BAD OF DRY KIBBLE AND WITH A WEEK IT WAS GONE SO I FIGURE  BY A 33 POUND BAG  AND SHE WAS STILL LOVEING HER FOOD UP INTILL LAST WEEK WERE SHE  DECIDED THAT I DON'T FEEL LIKE EATING IN THE MORING,BUT BY THE AFTERNOON SHE WAS HUNGRY AND ATE HER FOOD LIKE IT WAS NO BIG DEAL AND NOW SHE PULLLING THAT SAME THING TODAY. IN THE PAST MORING SHE ALWAYS HAD NO PROBLE EATING IT'S ONLY AFTER SHE TURN 7 MONTHS.  HER WEIGHT 54 POUNDS  SO I DON'T KNOW WHAT  IT GOING ON WITH HER.  SHE GETS NO TREATS  NO TABLE FOOD,, NO HUMAN FOOD, THE TRASH IS OUT OF HER REACH I PUT A LITTLE BIT WATER IN HER KIBBLE TO MAKE MORE SMELLING GOOD. THAT WAS WORKING FOR A WHILE  NOW IT'S NOT.  I FEED HER EAGLE PACK DOG FOOD WITH CHICKEN AND RICE BECAUSE OF HER SENSIVTIVE STOMACH  BEFORE THAT SHE WAS ON WELLNESS PUPPY DOG FOOD  AND WAS A BAD EXPERIENCE ALL IT DID WAS GIVE UPSET STOACH TROUBLE AND SOFT STOOLS  AT LEAST WITH EAGLE PASCK I GET THE BETTER STUFF  WITH HER STOOL. SO CAN YOU GIVE ME  SOME ANSWERS ON THIS ISSUE  WITH MY BOXER DOG.

Answer
Some dogs,like some kids become fussy for no reason,and sometimes like kids they do it to get attention,sometimes what will work is to put the food down and ignore her and the food do that for a few days

It is good you are not giving her treats or people food,because that will make it worse,so will mixing anything into the food,because as soon as you stop that,she will stop eating again

Another trick that will work is to give her the same amount of food,but 'rewards' for working on her training,even if it's a few kibbles at a time,at least she will get her meal although it does take a while sometimes

you also don't want to feed a large breed like a boxer once a day,as that can lead to bloat,which can kill a dog