note that the center swan is straight (& a slightly yellower green, indicating a different batch of glass) this was the traditional out-of-the-mould configuration that the finishers were instructed to produce, merely holding the head up until it cooled enough to be taken to the lehr.
the other 2 are examples of a later run, when i worked in the hot-end in the mid-70s. i encouraged the finishers to position the head in a naturalistic pose...it took no extra time or effort, but the finishers enjoyed the small bit of creativity it gave them. and each swan was unique, making them truly hand crafted, rather than merely semi-mass-produced.