Ive never had any of that happen in my 7 years of owning standards and bantams. I am even hatching chick right now that are from a large standard EE a tiny mixed bantam. Now if your rooster was a large fowl brahma or a bird that are ment for meat then i could see the squashing part.
some of my bantam prefer to be with my standards and my bantams are more dominate than some of my standards. A standard rooster is able to breed the bantam too. If your little baby is a male then I would get him 1-2 hens so he dosent get frustrated when mating season is at the highest.