Tonight we had our first taste of our homegrown chickens, and they were... a little rubbery . Very delicious flavor, very juicy, but kinda rubbery to bite through. I'm wondering if we did something wrong? They were 8.5 week old cornish x, free ranged in our backyard. They were butchered on Saturday morning, so have had 3 days to cure in the fridge. Any ideas?