The question is asked many times, "What's wrong with my chicken?" Not that there's anything wrong with that question, in fact, it is a perfectly fine question to ask. We all have asked that before, but hopefully this article can lead you in the right direction as to what exactly is wrong with you chicken.
Please note- This article is only intended as a guide. Further research is encouraged.
My chicken is puffed up and walking funny
This symptom is very common in that of an egg-bound hen. (Egg-bound means that she has an egg stuck in her and is causing her grief.) It is advised to help her pass the egg as soon as possible to cure the problem. To help her pass the egg, some suggest setting her rear end in a warm bath with some olive oil and gently massaging. You may have to repeat this process a couple times.
Chickens will also puff up their feathers at night or on chilly days, and this is normal.
My chicken has a cut and it's bleeding
This is a VERY common injury, but is usually nothing too serious. Isolate the chicken, and depending on how bad he/she is bleeding, you may have to wash the cut with hydrogen peroxide before applying Blu-Kote. This will help to kill any dangerous germs. Preventing infection is the top priority in this case, so keep the wound clean. Also depending on the severity, you may have to bring the chicken to a place where he/she is away from the others and able to recover quickly. Keep in mind- a chicken is much hardier than you may think. I had one hen get severely pecked on by older hens after a bad introduction. Much of her skin was gone by her tail and veins were very visible. I took her inside, sprayed the wound with Blu-Kote, and let her heal. She healed up wonderfully and is still alive to this day.
My chicken got frostbite
Unfortunately, frostbite can't be treated. The cells are dying or dead in that area and eventually the blackened area will fall off. The best cure for frostbite is prevention. Limit the drafts in the coop and apply petroleum jelly (Vaseline) to the comb, wattles, and legs.
My chicken is sooo loud!
Chickens are normally very vocal. They talk often just for the sake of hearing them self talk. Nothing is wrong with your chicken when they do this, but it may signalize that they would like treats. However, if the chicken's noise sounds like a call for help, check it out and make sure he/she is fine.
The egg shells are thin/odd
Thin and odd egg shells are common among newly-laying pullets. If you get a lot of odd eggs, add a side dish of oyster shell or another calcium supplement. The hens will take what they need and the eggs should return back to normal.
Stress may also cause the same problem. If there are predators, loud noises, or anything disturbing their daily lifestyle, the eggs can turn out odd. Try to minimize the level of stress your chickens endure.
The hens are very ragged and missing feathers
This can be many things. If you have a rooster, he may be over-mating your hens and needs to be away from them a few days. There's also the option of a "chicken saddle" which protects the hen's back from feathers being ripped out. Chicken saddles are available at many farm stores.
Check also for any bugs on the chickens' skin and feathers. Mites and lice are known to wreak havoc on a chicken's feathers very quick. Diatomaceous Earth (DE) sprinkled on the ground can help this problem. Manna-Pro also makes "Poultry Protector" that helps problems with mites and lice.
If none of the above are true, your flock may simply just be molting. Molting will last a few weeks and during those few weeks they will look very ragged. Supply them with extra protein and let them do the rest.
The comb/wattles are purple
Purple comb or wattles that are not frostbitten may indicate a respiratory or blood illness. This is often a very serious problem that may be contagious. Separate and isolate the chicken first, to avoid any possible spread to the flock.
Many things may be an illness with this problem, so report any additional problems your chicken may be experiencing to find out what is the cause and how to cure it. Often, dust from building materials may irritate the lungs of a chicken and cause respiratory issues.
There is blood in the stools
This is commonly an indication that your chicken (often chicks are more prone to getting it) has Coccidiosis. Cocci affects mainly chicks, though chickens of all ages are likely to get it.
You will need to separate and isolate the chicken/chick right away and start them on doses of Corid. Some advise to put the whole flock on Corid just in case any other members have coccidiosis and are not showing symptoms yet. Dosage and recovery time may vary bird to bird, and whether you are using powdered Corid or liquid oral.
The breathing is labored, shallow, or odd
Generally, this can signal a respiratory infection. Isolate the chicken as soon as possible, and if possible, contact a veterinarian for help and to schedule an appointment. Antibiotics are typically given to the chicken. Keep the chicken away from other chickens one week after symptoms have been gone to ensure that the illness should be gone. Do not eat eggs for at least 2 weeks from the hen on antibiotics.
Similarly, this may be an indicator of sour crop. With sour crop, the crop will feel abnormal and the chicken will be acting unusual. It is best to give the chicken individualized care, and feed them yogurt to help.
The chickens are fighting
It is not uncommon for birds to work out the pecking order. This just means they are trying to find out who is the alpha, beta, etc. However, some chickens may fight not related to the pecking order, or the pecking order fighting may be a bit out of control. Roosters are also prone to fighting. I recommend separating the fighting birds to hopefully calm them down. This works a majority of the time. Also, the "see but don't touch" method is highly effective.
Note- While not proven, I add garlic to treats if my chickens are too aggressive, and this has worked wonders for me and my flock.