Regardless of initial BCS, heifers ceased estrus at about BCS3. BCS7 heifers resumed estrus with less body condition gain. Estrus ceased at a threshold body condition, not after some amount or percentage of weight was lost. Therefore, heifers in above average condition can lose more weight and condition and still cycle, compared to average heifers. . It has rained, but most producers face winter without much standing forage, and probably low supplies of hay.
Corn is relatively cheap.
Cows can be fed high levels of their diet as corn, and whole corn works fine. But, you will have to feed every day.