Giant chickens would be more difficult and expensive to care for. Chickens are just about the right size already.
I can imagine one use for re-creating a critter and developing the technology to do so: if major pollinator populations were devastated, we could replace them.
But most solutions like that will probably come with all sorts of miserable unintended consequences; and some kind of mechanical solution would always be safer.
It wasn't mere chance (or nature) that made chickens "just about the right size," it was man. Centuries of selective breeding.
All meat-producing domesticated animals are bred with (chiefly) two properties in mind.
#1, feed conversion ratio. How many pounds of feed does it take to get one pound of animal at harvest?
#2, bone-to-meat ratio. What percentage of the animal's weight at harvest is bone?
There are smaller chickens (bantams) and larger (the Jersey giant) but chickens the size of the Plymouth Rock temd to dominate the meat market because they're in the "Goldilocks" zone for those two factors. Not too much, not too little, ... just right.