Rinse the white rice under cool running water until the water runs mostly clear, then set aside to drain.

Place the chicken breast in a medium pot and pour in 3 cups of water, making sure the chicken is fully covered.

Bring to a gentle boil over medium heat, then reduce to a simmer and cook for 12 to 15 minutes, until the chicken is cooked through and reaches 165 °F in the thickest part.

Transfer the cooked chicken to a plate to cool slightly and leave the cooking liquid in the pot.

Add the rinsed rice to the pot with the cooking liquid, stir, and simmer over low heat for about 12 minutes, stirring occasionally so it does not stick.

If the mixture becomes too thick or dry, add a small splash of water to keep it loose and lightly soupy.

Stir in the diced carrots and chopped green beans and continue to simmer for 5 to 8 minutes, until the rice is very soft and the vegetables are tender.

While the rice and vegetables cook, shred or finely chop the cooled chicken breast, discarding any tough bits or fatty pieces.

Add the shredded chicken back into the pot and stir to combine evenly with the rice and vegetables.

Stir in the pumpkin puree and the olive oil if using, and cook for 1 minute to warm through.

Remove the pot from the heat and let the mixture cool completely to just slightly warmer than room temperature before serving to your dog.

Portion into appropriate servings for your dog’s size and appetite, and refrigerate or freeze any leftovers promptly.