have you thought of good old tinned dog food,also if you have a freezer buy yourself a box of day old frozen chicks,if you feed pigeon make sure you clean out the crop area of the bird before feeding,also liver in moderation,most people with ferrets will have airguns for simply what you shoot give to the ferrets,i have bred and worked wild polecats over thirty years they have eaten most things in the british countryside including trout i have caught,also omega rings which i have soaked overnight is a good alternative but make sure they have plenty of water,all the best......
thanks very muc