I have eight years' experience on elecrict heating + patty feeding in spring.
4 frames or less colonies prefere to become sick than build up.
They are in the prison of their small size.
We could imagine that we have 4 frames of bees. In practice they cover only half of frames. Practically they may rear one frame of new bees. Minimum factor is short of feeder bees.
When after a month there are one frame new urser bees, they may rear maximum 2 brood frames. The wintered bees are almost died and the new bees must first compensate the dead bees. It takes 2 months that the colony starts to grow.
In a big hive, which covers 10 frames, may rear first 4 half size brood frames. It must be lack of nurser bees. Bigger or less bigger, the brood area is the same.
But then the hives get new nurser bees. a miracle will happen. The bigger the hiver, the bigger will be the brood area. The biggest hives may generate in second generation with heating 15 frames of frood. And brood area is from frame corner to frame corner.
A 5 frame hive can make 3 frames of brood. but 15 is 5 times more than 3.
The brood area is actually a ball. It has tree dimensions. You may calculate two options, the radius of brood area is 10 cm or 15 cm. how much is the volume if radius is 5 cm bigger?
The beekeepers cannot understand that biggest hives need help. Actually small hives need help but only big hives can help them. Along Spring you may steal brood frames every now and then from big hives and get smaller normal.
so lets look the big hive which occupye allredy 2 boxes. It has 15 fat frames of brood.
When those brood have emerged, they occupye 4-5 boxes 3 weeks later.
If we have at same time 5 frames of bees and 3 fat brood frames, the colony fills only one total box. After 4 weeks the colony fills 3 box. In my country it is allready a beginning of July.
At same time the biggest hive has 6-7 boxes.