Debby, first of all, there's no hard & fast rule that all dogs adjust with boiled form of food. My Labrador is fed 50gms of bonesless chicken mixed with rice ( khichri type ). We divide the meal into two and offer in the Noon and Evening. He also gives out more or less loose stool. The reason is very obvious, boiling converts the soft chicken and rice almost into sub-liquid so stools have to be a little loose as well.
Loose stools can be a problem as they may be difficult to clean off as compared to intact faeces which can be easily picked up using a scooper.
If you have fed raw food to your dog and it suites him, then what made you switch to boiled rice and chicken.Try to switch back to raw. Also, are you adding chicken liver into the meal? Try to remove it as it may be a culprit. Also, try to add raw bones which should give some solid base to his diet and improve the quality of the stool.