TL;DR : So far, so good. We’ve encountered some diseases, like fowlpox, seen some injuries but we aren’t spending the egg money before the hen lays the eggs just yet!
If you’re lucky you’ll never have to encounter any illnesses with your chickens. Some breeds are very resistant to illness. If you keep your chicken coop clean, your chickens well fed (especially when they need the most protein and fat, before winter) and happy, you should be good to go. Just pray for good luck. Farmers who have large quantities of livestock usually vaccinate their chickens against most illnesses. If you buy your chickens from a farm or a breeder be sure to ask them if their animals are vaccinated.
Ours weren’t and the only problem we’ve had in a couple of years is one of our chickens getting an eye infection. We were in Australia when it happened and I wasn’t able to identify the source of the problem at first (when I got back its eye was already all infected). Our roommates (you know the ones that weren’t really into chickens) hadn’t noticed because they didn’t want to go anywhere near them, so the infected wound had time to fester a bit. At some point I thought they had caught infectious coryza, but apart from her eye she seemed perfectly ok, so it was quickly ruled out.
As you can see from this picture she was doing absolutely fine except from her infected eye. It was especially hard to treat because should would rub her eye on her feathers very often throughout the day, constantly damaging the skin and re-infecting it.
I started her on a treatment as soon as I got back, but I wrongly stop the treatment a few weeks in because she was doing much better. Obviously a few days later it was all back to square-one. This is a mistake I often make, usually when I’m on an antibiotic treatment myself. It’s one I, hopefully, won’t make anymore and I hope you’ll take my mistake into account if you ever encounter this kind of issue.
Don’t worry, though, she is absolutely fine now.
It took medical treatment and eyedrops three times per day for a couple of months. Oh yes, as you can imagine getting drops of medicine into a chicken’s eye three times per day for weeks on end if not the nicest experience, for you or the chicken, but in the end she almost took them willingly (keyword: almost).
One of our chickens also caught a very benign case of fowl pox. This is apparently very common in the south of France because of the large numbers of mosquitoes we get over the summer.
Fowl pox is a viral disease in hens, turkeys and many other birds, characterized by lesions on the featherless parts of a bird. Hen may catch this from other birds, like pigeons, roaming around their feed.
A hard dark brown crust formed on the skin around her beak. We treated this daily with antibiotics and by disinfecting with alcohol and hot water and compresses until the scab fell off and she was all well again and pretty again.
Unfortunately I haven’t managed to find any clear pictures of this yet.
The best solution most of the time is quarantine and research
If you’re raising chickens to save money and not as pets, beware, getting your chicken to a vet might cost you quite a bit, especially if you live in an urban area. Every time we thought we had an issue we researched all the possible illnesses, meticulously ticking them off one by one until we only have one possibility left and then we got antibiotics from the drugstore/chemists’ (they had to order them because it’s not the stuff they usually have in display on the shelves). There are also non-profit associations that may help you identify your problems. If you notice any symptoms you should immediately quarantine a sick animal lest it infect others. If you still can’t be sure what your animal has, you should go to a specialist with it.
Getting vaccinated animals is a better idea most of the time, because one ill bird may infect and decimate your whole flock. Remember to always keep a close eye on your hens and watch out for any signs of possible illness. A chicken staying still in one spot is usually a bad sign!