What kind of land are you clearing? Is this brush-y, desert, fallow meadow, old crop land? Wet or dry?
The precursor question to what animals you might want might be "What kind of infrastructure and fencing are you interested in installing and maintaining?" And also "What kind of feed and housing are you willing to handle?"
We have steep forested land and we run a combo of pigs and goats to clear new areas. The goats can clear brush up to 6' tall (standing against the trunks/trees to reach up) and sometimes higher if they can manage to bend a tall sapling or mature brush down. They'll strip the bark, wood, leaves, and needles. We value that for fire mitigation.
The pigs are useful for cutting trails and working the soil. They root and help clear the land, they trample sticks and debris into finer pieces. Their poop mixes with the earth more readily than goat pellets that take a long time to break apart and work in. A large breed pig can easily move several hundred pounds (moving logs and boulders). They can dig huge holes very quickly. Smaller breeds are generally bred to root less and will do less 'land shaping' than the big pigs tend to do.
Fencing for goats and pigs is pretty similar, except that you need fences to come up at least 3-4' to keep the goats in, whereas a pig fence can stop at 2' high. But both animals will readily go under a fence- and also through it. So it needs to be tight and strong. And the best guarantee is to incorporate electric.
As far as predator protection, an adult pig is probably safe than an adult goat? Depends on the pig and its size and temperament I suppose. Miniature goats will be the most prone to predation. My experiences with minis are limited, but in the time I had them, I could not fence them in. They jump high, they fit through absolutely tiny holes, and the ones I had were infinitely more mischievous and bored than any large breed goats I had. They were utterly discontented to stay behind any fence. But maybe it was just the mini's I had.
Both goats and pigs need similar housing. Goats are safer up off the ground, pigs do well in low cave-like structures. Both animals will benefit greatly from fresh, fluffy bedding like hay or straw. Goats need dry conditions for their feet or you'll start seeing hoof rot, whereas pigs can handle constant moisture very well.
A good pasturing breed of pig might grow and sustain acceptably on pure forage, but they will benefit greatly from getting grains and other food supplementation as well. They are omnivores, afterall. Whereas goats can readily sustain themselves in a brushy/woody environment year-round, depending on the size of their territory and the size of the herd. They are browsers and primarily eat leaves, buds, wood, and bark. People often use goats to graze grassy pasture, but honestly it's not their natural diet and you'll need to supplement them with minerals. If the pasture they're on is short and stubbly, you'll probably want to offer a long and fibrous hay as well. They can develop rumen problems when they eat just short, wet grass. They get worms easier that way, too. But goats don't need grain, and IMO shouldn't get grain as they can't digest it properly. It also turns them into screamers.
Which is another point; pigs and goats can both be very quiet, or very noisy. The potential of pigs is happy pigs = minimal noise, upset hungry pigs = screaming noises. Happy well-fed goats = silent goats, hungry goats or goats with cravings = screaming monsters. Pigs are never truly silent, but I'd take pig noises over screaming goats any day!
As far as breeds go, I've become biased against floppy-eared goats and associate them with being overly vocal escape artists. Larger breeds can actually be easier to fence. My big goats are over 200lbs and they can't jump a 4' fence. They could when they were kids, but they're just too big and heavy to get that kind of clearance now. 3' they can manage, but not 4'. They require a much bigger gab in the fence to get through . Then again, they have more power and more ability to destroy wire fencing than a mini does. My minis would take advantage of any gap over 4" and escape. Electric fencing had to be 2-3" off the ground to keep them from going under it, and wires had to be no more than 4" apart to keep them from jumping through it. It was hellish. Way harder for me to contain. It was easy to pick a mini up, sure, but it's also easy to grab one of my big goats by the beard and escort them where they need to go. I've milked minis and big breeds, and I by far prefer the big teats on a large doe, and the satisfaction of watching quart jars zoom up to the full line in just a minute or two of milking. Compared to the tiny little teats of the minis that could only accommodate 2-3 fingers, fingers that were constantly covered in milk, and it took me twice as long just to get a pint of milk out of them. But some people have trouble handling large goats, or have wrist and hand ailments that benefit from the size difference. So there's a goat for every application!
The pain with goats, is if you're going to breed them (you mentioned meat production) they can take 3-5 years to reach their adult size. So a tiny baby goat will be a tiny PITA for a few years until it matures and finished growing. I think of this in terms of the first 3 years of raising my big packers, and how much EASIER they are to live with now that they're 'adults' at 5 years old. Those first few years saw a lot of destroyed fences and goat-damage from small, agile, bored kids spending all day long learning how to break a fence or gate. Whereas pigs (yes I know you didn't mention them, but I figured I'd suggest them since they're good land workers and might fit your needs), grow to adult size and mellow out in the first 6-12 months. For meat production, you can't beat pigs either. A goat will have a potential for 4 kids a year (unless she has triplets or singles, but they usually have twins). Those kids will dress out to just a few pounds of meat unless you get a big meat breed. Which, in this case, something like a boer goat might actually be what you want. You'll get way more meat off them and they might fit your needs better. A pig can produce over 20 piglets in a year. And those piglets can reach several hundred pounds within 6 months, even if they're a mini breed. Our minis grow almost as fast as full sized meat hogs, hitting 150lbs in about 3-4 months, but then they plateau and don't get much bigger, taking another 6-8 months to reach 250-300lbs. Whereas a full size hog might be 150-200lbs in 3-4 months (depends on how you feed em) and in another 8 months could be 800lbs!
- Need tight, strong fencing and/or hotwire, but fencing can be very short and they're otherwise fairly easy to fence compared to a lot of livestock.
- If producing meat, need grains offered to them, which are generally more expensive than hay. A robust litter of full size meat hogs can eat through 1 ton of grain in a month during peak growth period, putting on 10-20+ pounds a week.
- Housing needs are simple and rustic
- Fairly predator resistant
- Excellent at fertilizing and tilling the ground
- Will graze on pasture, rip out and eat roots, root up and eat rodents, etc
- One of the more dangerous animals to keep, being omnivores. Gentle loving stock is needed.
- Comes in minis (300-500lbs) and full size breeds (700-1,000lbs)
- Very rapid growth, making them good for meat production at the expense of higher feed costs
- If breeding, you need a boar around. They're not stinky, not excessively noisy or offensive. Our have never gotten aggressive when the girls are in heat, but we've made a point to keep very nice pigs. Boars don't "rut" like goats do, they just love on the ladies when the ladies cycle and sleep most of the rest of the time.
- Need tough, strong, tight, tall, and thorough fencing, ideally incorporating hotwire
- If supplemental feed is needed, grass hay suffices and is one of the cheapest livestock feeds to be had
- Need added minerals to their diets if on pasture, since pasture/grass/hay isn't a natural diet for them
- Housing must be clean and dry, and their safety & enrichment benefits from having places up off the ground (cable spools and such)
- In danger of predation from almost all predators, especially during kidding season, so fences are best built to also keep predators out (foxes, coyotes, dogs, eagles, bobcats, cougars, bears, etc)
- Goats don't really work the ground but they have mild poop that plants love
- Will eat the best of the best and move on. It's hard to force a goat to eat something it doesn't want to eat (they won't mow a lawn for you!)
- Fairly docile, safe, lovable animals unless you have a real stinker on your hands, or an unruly buck in rut
- Comes in minis (30-60lbs) and full size breeds (100-250+lbs)
- Meat turn-around in goats (and sheep) is minimal, but if you have a local market it could be in high demand. Meat breeds like boers are popular for their massive, bulky bodies.
- If breeding, you need a buck. Bucks are noisy and stinky and offensive in rut (pee in their mouths and froth it all over their bodies and get super musty smelling- like you can smell it 1/4 mile away or more). Most folks I know give their bucks a lot of space during the rut, even if they're normally a loving, trustworthy goat. I've only ever had a mini goat and rutting was the only time he's try to headbutt us without instigation or warning, the little pooper.
- Goats can be milked! A mini can produce anywhere from a quart to 1/2 gallon a day, more or less depending on the doe. Most minis have a higher cream/fat content in their milk than any large breed, making them popular for cheese making. Large breed goats can produce 1 gallon or more per day, again depends on the doe. Milking requires equipment and punctual daily schedules that go on for months. But the calories and good food you get are so worth it.
- Goats also come in fiber breeds! If you're into shearing and selling/working mohair or cashmere, fiber goats can do everything the other goats can (graze, meat, milk) + provide one more resource for you. Shearing must be done twice a year for the goats' health.
Sheep are similar to goats in many aspects but are easier to contain. My experiences with them is that they're less intelligent and more panic-prone than most goats. Sheep, if afraid of you or frightened suddenly, can jump and kick you or attack you or ram you. Not that a goat can't, but I've never met a sheep as tame as a goat can be, and have never met a goat as prone to the wild throws of terror like a sheep can be. I've never seen a sheep weasel through a tiny gap in a fence and defect from the herd for fun, like a goat will. But I've had to doctor many sheep that badly damaged themselves panicking and smashing themselves or others into a fence or gate, spraining or breaking limbs, trampling lambs to death, etc. when trying to move them from one pasture to another. I've never had goats damage themselves in flightly brainless terror like I've seen with sheep. But I've only worked with large meat sheep herds, not hand raised pet sheep. Sheep are dedicated grazers, unlike goats, and do best on pure pasture. They don't work the ground much, like goats, they need dry ground, like goats, and they offer the same variety of benefits as goats; fiber, milk, and meat. Lamb meat is often more lucrative than goat meat is. You can also get hair sheep that require no shearing.
Quail usually means domesticated coturnix. Coturnix are meat animals. I've got some in a large aviary and I have to be careful in there so that I don't step on them. They'll just stand there and look at my shoe bearing down on them and they won't move. They're also TINY. And fragile. They will not "home" in a coop like a chicken will and must be contained, not only to keep them in one place, but to keep them alive, as everything wants to eat them. They also won't do anything for you in regards to working the land. I garden in my quail pen. They don't dig, they don't trample earth, they don't destroy plants. They're a delight to keep, but they won't help with this particular task you've mentioned.
- Need 3-dimensional fencing
- Need specialized pasture and seed crops, with supplemented high protein feed grains
- Can live outside with little or no shelter year-round, very hardy in that respect. If in a large enclosure, have high ceilings to prevent them from spooking and hitting the roof.
- In danger of predation from almost all predators, including tiny predators like house cats, rats, and weasels
- They don't work the land much and are very gentle on the environment around them
- Utterly harmless to keep and incapable of hurting a person
- Quail weigh just a few ounces, usually (there might be some jumbo specialty breed out there)
- Meat turn around is excellent if you have a way to hatch their eggs
- If breeding, you need a rooster. A quail rooster is just like the ladies except he makes cool "warning chirps" sometimes and other cute little noises.
- Coturnix quail tend to lay almost daily and can produce over 300 eggs a year. Semi-wild quail varieties are seasonal layers.
Chickens are definitely turn a field of pasture into a field of dirt and poop if you graze enough of them on it for long enough. They will eat plants down to stubble and then dig until the roots are ripped out; IF they are grazed intensively in one spot. Chickens are harder to contain though (they dont' care about fences and can end up in the neighbor's field or your backyard garden if not given incentive to stay in one location). They are heavily predated on by all sorts of mammals and birds of prey. They are easy to raise though, all things considered.
- Need fencing to keep predators out more than to keep them in, but are prone to roaming if they get a wild hair or don't have enough food near their coop
- If pasture is lean, they need supplemented grain/feed. But a beautiful pasture can sustain them just fine as long as its available.
- Conventional ideas of coops are safe, dry, and strong. I've kept birds coopless though; they will nest in trees, in rafter of a barn, or wherever. The safer they are, the better, obviously. To me the safest factor is the roosts. Roosts 5-8' off the ground keep them the safest at night, with a roof over their head to keep nocturnal predators from plucking them off the perch. Whether those are indoors or outdoors, whether they're rafters or branches, the biddies won't be too picky.
- In danger of predation from almost all predators, including tiny predators like house cats, rats, and weasels
- They will graze, dig, hunt bugs, and poop with enthusiasm and help to work the ground. Their feces will NOT pass viable seeds like pigs and goats and rabbits.
- Obviously a pretty safe animal to keep unless you have an unruly rooster
- Comes in minis (1-2lbs) and full size breeds (3-8+lbs)
- Meat turn-around is decent, especially if you let hens sit their own eggs and raise their own babies on pasture. You'll have meat chickens in 3-6 months (breed dependent) that you spent no money or time on if you let them do it naturally
- If breeding, you need a rooster. A good rooster will watch over the hens, warn them of danger, and offer himself up/fight off a predator. A good rooster will respect you. A bad rooster will feed himself an no one else, run from danger, and/or attack you. All roosters crow and it can be quite loud, traveling 1/4-1/2 mile and waking out out of a dead sleep at 2am.
- Chickens also provide eggs, which is awesome, obviously! A good hen can lay 250-300 eggs a year.
- Chickens are very easily/cheaply replaced (by comparison to other animals) if butchered or predated on.
Turkeys are like chickens except they're far more prone to roaming (at least heritage are), are seasonal layers (usually), and they don't dig like chickens do. They graze very well though and can produce a lot of offspring and meat in a season, as they tend to be enthusiastic mothers. Double breasted meat birds are different. The meat turkeys I've helped raise lived next to their feeder and barely roamed 50' from it from chick-hood to butcher time. They could turn any patch of ground into a mat of feces very quickly, trampling the ground with huge heavy feet and laying in one spot all day. They generally don't lay eggs well and don't raise babies well.
Rabbits are a good choice for target grazing or tractoring, but won't work for free ranging. Generally, a free-ranging population gets predated to extinction. If not, they absolutely take over and become a pest. Pregnant does will dig burrows for their kits, and communities of rabbits will dig many kinds of tunnels; "oh s**t tunnels", as I call them; prolific small, shallow tunnels they dig everywhere to dart into quickly if a predator shows up, as well as cooling tunnels for the hot summer (they find get ground and dig special tunnels, almost like P-traps, that will trap moisture below them at the deepest point in the tunnel, with a smooth upper tunnel that stays moist and cool, but never "wet"), and they dig shelter and sleeping warrens, which are often separate from the others. So their tunneling might not be what you want in a field like this. Rabbits do not "home" to one place and will roam as food and predation directs them. But they are a rewarding animal to keep and can prime soil for you if needed.
- Need 3-dimensional fencing to contain and protect them- yes rabbits can just up to 4' high and simultaneously propel themselves through a 2x4" gap to escape.
- Will graze on brush and grasses alike, but will not do much digging or tearing up the ground if in a wired pen
- Can live outside with little or no shelter year-round, as long as they have escape from heat and rain/snow.
- In danger of predation from almost all predators, including tiny predators like house cats, and weasels
- Pleasant and peaceful animals to keep, but can inflict a lot of damage if you pick them up and they don't like it
- Rabbits come in miniatures (1-2lbs) and larger breeds (4-10lbs+)
- Meat turn around is excellent, with 1 doe producing 5-10 kits per month. They take 3-5 months to grow out, depending on your breed and preferred eating size/age.
- If breeding, you need a buck. Most rabbit bucks are the same as does. A few rare bucks will "tag" territory and spray it with a skunk-like smell. They're generally not mean or violent unless in with another buck.
- Rabbits also produce fur/hides and fiber. Picking breeds/individuals with luscious fur can make for good hide production. Or raise angoras for fiber! Though angoras are a whole 'nother beast and can't quite be kept the same as the standard meat rabbit.