For VERY early food butchering whatever wagon animals you got will see you through to the winter at the very least.
This.
Also if you invest in a military (i.e. 2 dwarves, proficient weapon users, put in squad of 2, have train permanently) then such elite dwarves can easily run down wild animals and kill them. Shooting wild animals is also
very good marksdwarf training and again has the benefit of filling producing more meat than the dwarves can possibly eat.
The other major, very major, food source, is caravans. The thing about caravans is they always bring what you lack. So if you cook all your meat and fish and cheese into prepared meals, then they'll see that you have none of those foods and bring you heaps and heaps of it. So you can produce a massive stockpile of food just by buying up everything the caravans bring, and processing it so they bring more. An advantage of caravan meat is it always comes in stacks of 5, which becomes size-20 roasts. That's way more food than you can fit in a barrel, so storing such prepared meals in a barrel-less stockpile is a very space-efficient way to store food.
Caravans will also easily supply your booze industry. Again the trick is to brew all the plants you have, then the caravans see you have no plants, and bring heaps and heaps. Dwarves only bring plump helmets, but humans and elves will bring a wider variety of plants for brewing. An added advantage of this kind of plant supply, is you can additionally cook all the seeds. Actually because dwarves drink twice as often as they eat, and brewing plants produces about 2 seeds per plant, you could just about both booze and feed your fortress by brewing plants and cooking the seeds. That'd be a nasty diet though because seeds are low value. But cooked seeds are a good food source in a pinch, because the seeds are so readily replaced by buying more plants from caravans. You could easily get 200 plump helmet spawn just by buying all the plump helmets from the dwarvern caravan and brewing them. So don't be afraid to cook such seeds. And also consider that embark plump helmets are a good buy, because when brewed you get 5 booze and about 2 spawn per plant - that's worth 12 embark points, but the plump helmet only costs 4 points. So seed cooking is nasty, but it's a dirt cheap food supply.