[Michael Bush]

Checkerboarding is done above the brood nest... You can open the brood nest. If the bees can fill the gaps with festooning bees you can make the gap with no real risk. Not many hives can take every other one empty. It would have to be booming and have a serious excess of bees...

 

[Michael Bush]

The best place to feed empty bars is between brood combs because it no only prevents swarming and encourages expansion, but it results in very nice combs if the combs it is between are very nice combs. Brood combs are very consistent. Honey combs are not.