Spatchcock the chicken: Using scissors or a sharp knife, cut backbone from chicken.
Turn chicken skin-side up and press firmly on breastbone to flatten. Pull firmly on each leg to pull from socket and press down to flatten.
Using scissors or a sharp knife, cut backbone from chicken Set aside.
Combine juice and zest of lemon and orange, olive oil, garlic, rosemary, salt and pepper in a small bowl and whisk to combine.
Pour over chicken and refrigerate 1-24 hours.
When ready to cook, preheat grill to medium for indirect heat (for a charcoal grill, bank coals on 1 side of grill; for a gas grill, leave center 1 or 2 burners off).
Remove chicken from marinade, place skin-side down over direct heat and place bricks on top of chicken.
Close lid and grill (approximately 450°F heat) for 5 minutes to brown skin.
Move chicken to indirect heat (or turn heat off directly under chicken), cover and grill 15 minutes longer.
Remove bricks from chicken, turn chicken skin-side up, replace bricks on chicken and grill indirectly an additional 20-25 minutes, or until thermometer inserted in thickest part of thigh registers 170°F.
Remove chicken from grill and allow to rest 10 minutes before cutting into pieces and serving.