I second Marches Farmer re blackthorn - evil stuff and the scratches take months to heal. It must exude something horrible and makes maintaining the hedge a difficult job.
What you can grow will of course be governed by whereabouts you are in the country. Up here in the south of Scotland, we have these in our mixed species hedge:
Hawthorn around the outside.
Inner layer: some hawthorn (edible berries and the animals are careful enough to be able to strip off the leaves they can reach);
hornbeam;
beech for winter cover and looks;
scots pine for evergreen cover for birds and animals plus eventually cones for birds;
crab;
bird cherry;
Mirabel (the best wild plum for our area),
roses various, including rosa rugosa (favourite with councils) which produces big fat hips which chickens love so much they jump up for them. You need to keep this under control as it is thicket forming and a bit of a brute, but pretty and evergreen;
elder for flowers and wine (will die off eventually and leave a gap in your hedge, but great if you can keep it going);
blackcurrant - odd I know but I had several which had rooted so added them to the base of the hedge - feeds some birds and maybe voles. Redcurrant would suit chickens and wild birds better - they love those;
rowan;
occasional oak;
ash - branches good for sheep, seeds for wildlife;
a few birch;
hazel - nuts and dense cover;
Field maple;
Alder if you have a wet corner.
We also have a wider 'wildlife strip' where trees can develop better and small animals and birds can nest more safely away from livestock and dogs. In this area we grow full sized mirabels; ash; scots pine; elder; holly; hazel and loads of willow - willow is superb for early pollen and maybe nectar (not sure) for bumble bees - they buzz around the pussies when they open in swarms (not really swarms because they're not honey bees

). We use a variety of willow types, from tall ones, quick growing ones, ones which fall over, reroot then grow to form a thicket, all of which have slightly different flowering times. Willow is also of course the best animal feed. Bramble ( brilliant for creatures to set up home in). Dog rose which forms prickly thickets, small and pretty; Balm of Gilead (a type of poplar I think) which wafts the most wonderful scent from the very first buds starting to grow until leaf fall, and is also edible for sheep.
A couple of years back we planted out Juniper, not so much for wildlife benefit, although they have berries, but because it's a native to this county but there's hardly any left. It grows incredibly slowly

We have a new coppice with willow, ash and hazel, all of which can be cut and given to the sheep.
Sorry but I don't know what pigs would eat apart from apples. I think crabs give them belly ache, so would need to be a cultivated variety.
We have found by hard experience that you can't just let your livestock wander around the hedges and eat at will, because they will destroy the lot. Ours are fenced on the inside as well as out, far enough back that animals can only reach the tips as they grow - including cattle from outside, for which we now have added top wires so they can't jump in or reach over - a huge cow hopping the fence is a hilarious sight but not what you want to see.
To feed the leaves and branches we cut them down and dump them in the pasture as needed.
Sheep have destroyed our orchard at least twice and damaged bark to let in canker. Sheep love fruit trees including the bark, so they do need some tough protection. Hens also love to roost in the branches, in the day as well as at night if you let them.
A down side of hedges is that foxes can lurk in there too.