Even pullets can grow a comb, so your thought process that just bc your pullets don't have that, doesn't mean other hens don't, therefore that alone is not a fool proof method of sexing a chicken.
I was trying to answer a question someone asked and it made me start an acct and come here, lots of work just to answer a question, but I made the choice to go through all this instead of moving on. 🤷♀️ Thanks