Now then, reports of Bigfoot are always mixed. The prevailing theory is that the creature is about 2-3 meters tall, large, hairy, ape-like, and over 230 kg. That is mildly believable. Apes can have offspring that are larger than what is expected.
We have a good example of this in person sapiens. When you start throwing in some outrageous claims, that is when it becomes difficult to believe. Bigfoot as a species is also very difficult to believe. An entire species of giant apes -- relatively undiscovered? It is hard to believe that they would be undiscovered. That being said, there are many species that we have yet to discover, but I would imagine that these species are mostly bugs, birds, aquatic, and minor deviations from known species. Such big species such as the concept of a giant ape (like a bigfoot) being undiscovered is unlikely at best.
I'd like more information about this special you watched. A friend of mine is a cryptozoologist. He fails to follow the scientific method in most of his endeavors, so his work is rarely credible. IDK if that is how many cryptozoologists work... but that is how my friend works...