Lesser White-fronted Goose x Ross's Goose Anser erythropus x Anser rossii (or Chen rossii)
This bird had been around for a number of years and its identity is not 100% certain. I think Ross's or Snow Goose involvement is fairly clear and some Anser involvement seems fairly certain too. In most respects Ross's Goose x Lesser White-fronted Goose seems the best explanation.
The small bright pink bill suggests Lesser White-front, although we might expect a Ross's Goose x Lesser White-front to show more white on the forecrown. Many captive and feral Lesser White-fronted Geese are not pure, having some (Greater) White-fronted Goose ancestry - this may be the explanation, or it may simply be that the hybrid shows less white on the head compared to either of its parents.
It has some black on the cutting edge to its mandibles and a very slight 'grinning patch' - the possibility of Snow Goose involvement is not completely ruled out.
Although this bird seems to have a bit of a bulky rear end there doesn't seem to be any convincing evidence for a domestic goose involvement.