To your follow-up questions:
- What age to buy in I guess depends on the finances. For sure it's easier once they're older and feathered so they can go straight outside and don't need as much protection from predators. I managed to farm out my young incubator-hatched goslings last year but based on their experiences and my own experience with young ducklings, they're very mucky indoors so unless you have a convenient predator-proof outbuilding, young goslings would be a pain. But then it depends how much more you'd have to pay for an 8 week old or something. Even then you have to be slightly careful - they can still drown and stuff - but they're less at risk from crows or small predators.
- Mixed sex gaggles are loads easier than other birds. The only time I separate out the ganders is in breeding season and I've a problem this year because I've got an extra gander so not quite sure what to do about him - think he'll be living with ducks or something. If you're getting young ones in for Christmas, they'll all be fine until then. And you can eat both sexes - just the geese will be smaller than the ganders.
There was some mention above about plucking etc. If you're doing this commercially, you will need to meet meat processing regulations. So you don't have to have the paperwork for transporting live animals around that you need with four legged creatures but it'd probably be easier if you can find a local abattoir which would be happy to handle them - or somewhere else that already has the relevant hygiene certificates. Otherwise you have to get set up with the correct dispatching and handling processing - they have to be stunned before dispatch, handled in facilities that have a hygiene certificate and then hung/stored in a certified cool room (and collected rather than delivered because otherwise you need to be able to transport in a cooled vehicle too).
H