What kind of raft are you talking about? greens of any kind like romaine lettuce would work is this a Canada goose your referring to? if you feel it's in danger see if you can find someone that rehabs water fowl they may come and help
Where are you located? Does it appear to be a wild goose? If it is a wild Canadian goose you should call your local wildlife authority as they are protected and the wildlife authority should be able to assist. In the meantime, do you have any lettuce or any kind of melon in the house? If you do you could take that and some clean water out to the raft, put it within reach and see if the goose will eat it. Some grass clippings might also work but geese are pretty picky about their choices of grass so don't be surprised if the goose just ignores it. Does it appear that the goose is injured, has been shot or in some way wounded? You may need another person to get the goose if it is injured and wild as it will probably try to get away and may further injure itself. Good luck and bless you for wanting to do something to assist this bird. Let us know how things work out.
