I have two solutions.
When I grill, I use thighs or legs, which are more flavorful anyway.
Also, there is a local brand called Redbird Farms. All veggie diet, no juicing and hand cut. You really can taste the difference. Costs a little more than the national brands, but chicken is cheap so it's no big deal.
We raise all our own meat, including about 25 chickees a year.
We have had some ridiculously large birds (broilers) in past years. Like over 15lbs. They are bread to grow very fast. 12 weeks is about as long as you can keep them alive, or they get so large, they cant walk
They are all free-range, with organic feed only. Free range is relative, I suppose as when they get bigger they just sit by the feeder and eat...all day.
Seriously good meat though.
All veggie cannot be free range. When a chicken comes across a bug, the veggie diet goes out the window.
Of course I dont know what span we are talking here and I dont know the source of these birds but...
There was a place we used to go in 72(?) called “Chicken World” (which does not seem to have any connection to the present day Chicken Worlds that I can find) that served fried (broasted) chicken with pieces about 4 times what was the normal size at the time. They were like smallish turkeys. Never a tough piece, never a dry piece.
Ive raised some huge individuals from a number of different heritage breeds and mine have never caused me any of these problems either.
Like so many foods today from spinach to apples, chickens and pork, the best tasting and textured and often the most nutritious strains were pushed out of the way for a strain that had some other characteristic like ship-ability that destroyed that product and turned it into something the consumer no longer really wanted. It doesnt help that our socialist agriculture policies for the benefit of the banks has turned all of our food production into a industrialized mishap of misfeeding and mishandling but thats another conversation.
Id bet dollars to donuts that its a simple fact of poor management of the genes in what is being raised. Time to go back to the drawing board.