I'm not a vegetarian, or vegan.  I know that humans are omnivores.  I also know that early humans were almost entirely carnivores, before they evolved enough to eat (digest) vegetation, especially starch. 
This is not a blog about whether or not we should eat meat, because we should.  What I, and many vegetarians, and animal right activists are angry about is our methods behind livestock mass production. When you buy a carton of eggs, chances are there will be a picture of a pretty little farm, with green fields, and animals roaming around freely.   It's not like that anymore.  Sure there are still farms you can go see in the countryside, but unless you purchase your eggs from the side of the road, your breakfast is coming from one of the mass producers.  Same goes for beef, pork, and poultry.  
We like to think there are laws in place to protect animals from cruelty.  There are, but they are of extremely low standards, usually only cover pets and wildlife, and some animals, including chickens, do not have the same laws protecting them as cows have.  So although most "farms"... let's call them what they are - factories.  Although most factories comply to these laws, the animals they produce still suffer unimaginable existences.
Egg laying chickens are kept in tiny cages that are stacked on top of each other.   The cage is so small, they are unable to move. Unable to move out of the way of the other chickens shit that falls through the mesh cages and all over the chickens.  The chickens will spend their entire lives in these cages.  The only escape they ever have is death... which is a common occurrence.  The first thing most "farmers" do in the morning is go through all the cages and pick out the dead ones.  They do this every day, because chickens die from stress, infection, and injuries from the cages, every day.  
If the chicken is lucky enough to be chosen for "broiler meat", they do have some liberty to move around the poorly ventilated warehouses with tens of thousands of other chickens.  Since chickens naturally form hierarchies and social communities and families, being housed like this disrupts that instinct and they fight each other. So what the farmers do is cut off their beaks.  Many chickens die from this, either from infection, or because they are unable to eat.
Most chicken food (unless organic) is filled with grown hormones.  We keep things cheap by making the chickens grow as big and as fast as possible.  Many grow to be so large they are unable to walk, and are usually trampled by other birds, until they are found by the "farmers" who usually beat these disabled animals to death.   They are not euthanized, or given care, they are literally beaten to death.
If they're lucky to survive all of this, eventually the "farmer" hires people called "chicken catchers" who come in when the chickens are sleeping, and grab them by the legs, 4 in each hand, and throw them into transport bins (headed for the slaughterhouse).   I know many people who have worked at chicken farms as catchers, and they all tell the same tale.   To prevent the chickens from clawing at them and squirming around, they intentionally break the chickens legs.  I've even heard some of them talk about how they made a game out of throwing them through ventilation fans.   "They get shredded up to pieces!.... Feathers flying everywhere!" as they laugh and joke about it.   
When slaughtered chickens are hung upside down, electrocuted (which does not kill them) and their throats are slit, and they are left like that to bleed out and eventually die.   It is not a quick death, but it's their demise is the only mercy these animals ever get to have.  

This is all completely legal by the way.  There are no laws that protect chickens from cruelty. 
This is just what happens to chickens.  Although there are laws that protect cows and pigs, they do not prevent much of the suffering inflicted on them.   It is common practice to castrate baby pigs and cows without painkillers.  They literally just cut them open and tear their testicles out.   Cows have their horns burned out of their heads, again without painkillers.   Depending on what they are intended for, they are housed in very cramped, and disgusting conditions... not the kind of place anyone would want their food to come from.
That's the thing. We don't see it.  All we see is cows grazing the pastures of small-time farmers, or a handful of colourful chickens and geese pecking at the ground of a small-time farmer's yard.   We watch the commercials where guys in overalls driving tractors, but it's not the truth.  Raising livestock like this is a difficult and expensive process.  It's much easier and profitable to run things like a factory would, and that's why we get the majority of our food from places like that. 

Because we don't see what goes on behind closed barn doors, we don't think twice about where our food actually comes from, and is actually produced.   We like to believe that we hold high standards, and this type of cruelty only happens in countries where there are no animal rights.  The truth is very disturbing, disgusting, and something the "farmers" here do not want you to know... because if you did, you would most likely turn vegetarian.   Even if the cruelty doesn't bother you, the conditions these animals are raised in, is enough to turn stomachs. 

Before you comment, I really wish that you will look into the evidence given by the animal right activist groups, that they are using to try and petition for more animal rights.  You don't have to join, you don't have to care, but at least open your eyes to what is happening right now, to the food you eat, the food you feed your family!   If you buy meat commercially, you are absolutely and directly contributing to this.   If you can't stand to watch a cow be slaughtered, you shouldn't be eating them.
Now that brings me to the part about vegetation.  In flamingnut's blog, he asked "do you think plants like to be eaten?"   The answer is yes.  Many plants "want" to be eaten, as it is how they reproduce. (There are even kinds of trees that need to be burned in a fire in order to give off their seeds) Take any kind of fruit for example.   The fruit tree produces fruit that has seeds in it.  Animals eat that fruit, and the seeds, and the animal later defecates the seeds, scattering them around.  Their poo also provides fertilizer for the seeds to grow.   Animals and plants help each other thrive.  This intricate balance in nature is beautiful!   Everybody takes what they need, and nothing ever goes to waste.   

We are the only exception to nature's system.   Why?  Because nature doesn't work toward goals in monetary profit.   The objective of any company is growth... at a certain point we faced nature's limitations, and have manipulated it to work for us, to grow, and to gain more.   Cows are given hormones to produce more milk.  Calves are kept in tiny cages to keep their meat tender - we call it veal.   Chickens are forced to sit there in a pile of chicken shit, so we can have eggs every morning.  The list goes on.
If we all got our food from the local farm, I'd be ok with it.  If we raised our own food, I'd be even happier.  I personally live in a great area when it comes to fresh, local produce. So instead of going to the grocery store to support big corporate, and what they do in the name of profit.  I go to the farm down the road, fork out a little more than I would pay in a grocery store (not much though... I actually pay less for some things).  No, not all of my bell peppers look exactly the same, nor are they huge.   The chickens I buy are also normal chicken size, and not the size of a small turkey.   Corn is in season now, and it's a million times fresher and juicier than anything I ever got in a can, or even in the "fresh produce" department!  If anyone here knows someone who raises chickens, you're probably sick of them by now, because they keep trying to pawn eggs off on you.   I have pear and apple trees in my backyard, and my landlord even left us a small piece of land that he said we can turn into a veggie garden. I intend on starting that project next spring :)     You don't have to support these industrial farms.  They're evil... they pay migrant workers under the table, abuse their animals, and use harmful substances that we end up eating.   Why would any conscious person want to support that?  To save a couple cents? So you can buy everything in the same store?  There's no excuse.... it's just easier for you, that's all.