Originally Posted by NineOne
... I imagine part of the trick here is the use of ground chicken breast, rather than just ground chicken, ...
Welcome to the forum, NineOne.
After watching a certain episode of Modern Marvels, I would suspect that unground chicken is used.
Processed turkey, on a large scale, was the marvel I saw being produced. Basically, several turkeys' worth of breast meat treated with a binding solution was compacted into a cooking bag before the bag was sealed. The bag was then pressure-cooked.
Between the binder ingredients and the sealed bag, the individual breast pieces stuck together in one big conglomeration. Pressure-cooking just cooked it faster.
I believe this is the way big slabs of roast beef (like the ones Arby's restaurant slices) are made.