Introduction To Reproductive Tract Illnesses In Hens
There are multiple types of reproductive tract diseases that hens can develop such as reproductive cancers, oviductal impactions, salpingitis, and egg yolk peritonitis. Though any female chicken can develop reproductive tract issues, chickens typically exploited for their eggs in industrial settings, such as Leghorns, Red Stars, and other sex-link hybrid hens, face an increased risk of developing reproductive issues due to the way they have been selectively bred for increased egg production. Reproductive tract illnesses are especially common in these breeds and should be at the top of your mind if they start showing signs of illness, especially if they are over two years old.
Depending on the reproductive tract issue at hand, a hen’s abdomen may be tight and fluid-filled like a water balloon, squishy with firm structures present, or extremely firm. Often, a chicken with a distended abdomen will develop fecal matting on the feathers below their vent. They may also develop labored breathing due to the pressure the abdominal fluid or masses put on their air sacs, and they may have a dark comba fleshy crest on the head of the domestic chicken and other domesticated birds and wattles. Some reproductive tract illnesses result in secondary cropA crop is a pouched enlargement of the esophagus of many birds that serves as a receptacle for food and for its preliminary maceration. issues or air sacculitis. Though chickens can be affected by primary crop issues (such as sour crop), reproductive issues should always be considered and explored in hens who develop crop motility issues.
If your female residents are actively laying, be sure to pay attention to their eggs, looking for abnormalities such as soft-shelled eggs, or the passing of impacted egg material or lash eggs (both discussed more below). Also watch for any hens who stop laying eggs unexpectedly, as this could also indicate an issue. Check out our Resident Laying And Implantation Record Systems to help you keep track any pertinent observations related to egg laying.
Suprelorin implants may help prevent these reproductive issues from developing and can help manage certain conditions that are already present. If Suprelorin implants are an available option for your residents, you should discuss an implant protocol with your veterinarian. It may be wise to prioritize implanting leghorn and sex-link hybrid hens, since they are at an increased risk of developing reproductive issues, but again, any female chicken can develop reproductive issues. (If you’re not familiar with Suprelorin implants, be sure to check out our detailed and veterinarian-reviewed resource here.)
Reproductive tract illnesses must be diagnosed by a veterinarian to determine the appropriate course of action. Your job as a chicken caregiverSomeone who provides daily care, specifically for animal residents at an animal sanctuary, shelter, or rescue. is to identify if a hen is showing signs of reproductive illness, and arrange for them to be evaluated as soon as possible. Common reproductive tract diseases include:
Salpingitis
Salpingitis, or inflammation of the oviduct, is one of the most common reproductive tract diseases in chickens and is often an emergency issue. Salpingitis can have an infectious or non-infectious cause. Bacterial or viral infections can result in salpingitis- common infectious causes include E. coli, Streptococcus sp., Mycoplasma gallisepticum, Acinetobacter sp., Corynebacterium sp., Salmonella sp., and Pasterella multocia. Non-infectious causes include trauma, such as from passing a large egg or damage to prolapsed tissue. A common sign of salpingitis is the passing of “lash eggs,” which are not really eggs but are rather caseous material (cheese-like pus). Lash eggs can be various sizes and shapes and are typically firm and rubbery with a distinct smell. When cut open, they may have liquid pockets and will also have various layers.
There are many online sources that say there is no treatment, and the hen has no hope of survival. This is not true. A veterinarian can evaluate the hen to determine both the cause and the severity and will typically perform an ultrasound. It is important to try to establish a relationship with a veterinarian who has access to an ultrasound machine as this is a key diagnostic tool when dealing with salpingitis. Local veterinary universities may suggest performing a full CT on the chicken, if she is stable enough for anesthesia, to get the most answers as to what exactly is the cause and to determine the best treatment approach. Treatment typically consists of antibiotics, anti-inflammatory drugs, and potentially a Suprelorin implant. If medical management is not successful, your veterinarian may recommend surgical removal of the oviduct (salpingectomy), though this is a complicated and risky surgery.
Impacted Oviduct
Hens can develop an impacted oviduct for a variety of reasons including infection, inflammation, neoplasia, or a combination of these. Salpingitis is often an underlying cause of oviductal impaction. Whatever the underlying cause, the result is the inability of a follicle or egg to pass through a portion of the oviduct. This can often be a fatal condition if not addressed early on in the disease process.
Depending on where in the oviduct the impaction occurs, the impacted material may simply be egg yolk (the material that surrounds a developing oocyte in a follicle) or may be a shelled egg. Despite this blockage, the hen’s ovary will continue to release follicles, which will add to the impacted material. In some instances, if the underlying cause resolves, and there is only a small amount of impacted egg material, the hen may be able to pass the material on her own- this is generally referred to as an acute oviductal impaction. Oftentimes, however, this is not possible, and the impacted material is added to every time the hen’s ovary releases another follicle (upon surgical removal or post-mortem examination, if the impacted material is cut open, you can often see the various layers of egg material that were added to over time). This is then classified as a chronic oviductal impaction which results in a serious, but slow growing problem with each subsequent follicle adding another layer to the original impaction. This, compounded by the chicken’s naturally high body temperature of about 106-107 degrees Fahrenheit, results in the egg matter essentially cooking inside the chicken’s oviduct.
If you see a drastic decrease in egg production in a resident who has not been implanted, you should closely monitor her for clinical signs of an oviductal impaction so that you can get her to the veterinarian before she is showing signs of a serious issue. Oviductal impaction can be confirmed via ultrasound, but can sometimes also be palpated during a physical examination depending on the size, which can range from very small up to soft ball size or larger. Hens with chronic impactions often have visibly distended abdomens that may be completely firm or feel a bit fluidy, but do not have the same water balloon feel as the abdomen of an individual with reproductive tract cancer. Severe impactions can result in oviductal rupture, which could then cause secondary egg yolk peritonitis (described next).
In some cases, salpingectomy may be recommended but, again, this is a complicated and risky surgery. If, for whatever reason, surgery is not recommended, the condition can sometimes be managed temporarily through the use of regular non-steroidal anti-inflammatory drugs (NSAIDs) and a pulse antibiotic therapy (regular intervals of antibiotics interspersed with time off antibiotics) to keep infection at bay. This is not curative though, and depending on the severity of the issue, may not provide the individual with a good quality of life. Whether surgical intervention or medical management is pursued, the hen will also benefit from Suprelorin implantation, if possible. Always discuss treatment options with your veterinarian.
Egg Yolk Peritonitis/ Coelomitis
Peritonitis is inflammation of the peritoneum (the membrane that lines the abdominal cavity). Egg yolk peritonitis (also called EYP or Egg Peritonitis) occurs when there is egg material present in a chicken’s abdomen, causing the inflammation. Egg material can enter the abdomen in various ways, either from being released from the ovary directly into the abdomen, by being expelled back out of the oviduct for some reason, or from a ruptured oviduct (often due to a severe impaction). Bacteria quickly grow in the resultant environment.
This is an unfortunately common disease in breeds used in industrial egg production, but can affect females of any breed, including large breedDomesticated animal breeds that have been selectively bred by humans to grow as large as possible, as quickly as possible, to the detriment of their health. chickens, and typically does not end well if left untreated. Depending on the underlying cause of the inflammation/ infection, it is not uncommon for the chicken to make a full recovery with appropriate treatment, especially if there was not an underlying infectious process causing the issue.
On a veterinarian’s recommendation, egg yolk peritonitis can be treated with intervention (draining of abdominal fluid), antibiotics, anti-inflammatory drugs, and potentially a Suprelorin implant to give them time to recover, though prognosis is highly dependent on what caused the egg material to end up in their abdomen in the first place. If abdominal fluid is collected, it can be cultured to identify bacterial causes and to determine what drugs the bacteria are susceptible to. It’s a good idea to request a complete blood panel if egg yolk peritonitis is suspected.
Reproductive Tract Cancer
Reproductive tract cancer (ovarian or oviductal cancer) is the most common source of tumors of unknown origin in hens. It’s often the result of excessive egg laying through generations of selective breeding, and typically affects hens when they are about two years old (which is usually the age at which they are considered “spent”). Breeds typically used in industrial settings are commonly affected because they have been bred to lay such a large number of eggs. Anecdotally, Leghorns seem to be especially prone to developing reproductive tract cancer.
Because it is more common in breeds used in industrial settings, and because it often develops at the time these hens are no longer considered profitable, many veterinarians may not have had the opportunity to see this condition firsthand. Ultrasonography, or a more detailed CT scan, can be used to confirm a suspected reproductive tract cancer diagnosis, but not all veterinarians have experience imaging a chicken’s reproductive tract. These cancers often present as large amounts of accumulated abdominal fluid- much more than is typically produced from egg yolk peritonitis. This fluid carries cancer cells to other areas of the abdomen and throughout the body via the bloodstream. As it spreads, the intestines often become affected and become thickened and firm. This thickening can result in emaciation and secondary crop issues because food has difficulty passing through the intestines.
Fluid can be removed from the abdomen using a needle and syringe, but this practice must be taught to you by a veterinarian or highly experienced care expert. Improper technique could result in infection or damage to internal organs or air sacs. In some cases, it may be better to have the individual sedated during this procedure. Your veterinarian can also explain to you when you should remove the fluid, as removal actually encourages the creation of more fluid, so removing fluid too frequently can worsen the condition. However, fluid build-up can also put pressure on air sacs and can cause birds to be very uncomfortable, so fluid removal must be done thoughtfully. Cancerous fluid removed from a chicken’s abdomen is often translucent rather than opaque (either a translucent yellow or completely clear). Reproductive tract cancer produces such large amounts of fluid build-up that it could be possible to remove up to a liter of fluid from a chicken’s abdomen at one time. This fluid is typically sterile, so antibiotic use is not usually advised. Chickens with large amounts of fluid in their abdomen will often have visibly distended abdomens, and their abdomen will feel fluid-filled and tight, much like a water balloon.
There is no cure for reproductive tract cancer, though there are drugs that your veterinarian can recommend, such as Tamoxifen, that can manage the disease for a time. A chicken suffering from reproductive tract cancer could potentially be given a Suprelorin implant to remove the extra stress of egg production. In addition, it has been found that supplementing with flaxseed can help alleviate ovarian cancer severity and incidence in chickens.
Internal Laying
Internal laying refers to the accumulation of egg follicles in the chicken’s abdominal cavity. This happens when follicles change direction and are discharged internally instead of exiting out of the oviduct and being laid. This could be caused by a number of conditions, such as inflammation, infection, or cancer (or following a salpingectomy, if the ovary does not regress- more on this below). Sometimes, internal yolk can be reabsorbed by a healthy hen, especially if it remains intact and does not rupture, but shell membranes, hardened egg masses, and ruptured follicles can quickly cause secondary problems, and repeated internal laying quickly compounds health risks including egg yolk peritonitis. In severe cases, surgery may be required to save the chicken’s life, though this intervention can carry significant risk. You can potentially help an individual recovering from internal laying with Suprelorin implantation.
Cystic Right Oviduct
In chickens, like most other species of birds, only the left ovary fully develops and is functional. The right oviduct regresses but can become fluid-filled. A large cystic right oviduct can contain a pint of fluid. This can compress a hen’s vital organs and put pressure on air sacs. Ultrasonography can confirm a suspected cystic right oviduct diagnosis. You can usually drain the fluid safely without surgery but you must consult an avian expert first, as this is not always necessary, and you must be taught the proper technique to prevent causing complications such as infection or organ damage. Fluid build-up from a cystic right oviduct develops much more slowly than fluid build-up that is the result of reproductive tract cancer. Fluid is often clear in color but may be opaque and cloudy with visible floating particles present.
Soft-Shelled Eggs
Chickens who are actively laying eggs need a balanced diet to meet the demands of egg production. Poor nutrition can cause soft-shelled and malformed eggs, which can cause cloacal prolapsethe falling down or slipping of a body part from its usual position or relations and egg-binding (described next). Egg production demands a lot of calcium, and breeds used in industrial egg production can easily become deficient in calcium. The eggshell is developed last, and consists mostly of calcium carbonate, absorbed through diet and taken from their bones, so appropriate amounts of calcium are essential to a chicken’s health, especially if they overproduce eggs. If you feed the chicken’s eggs and shells back to them, they can replenish some of the lost calcium (you can read more about what to keep in mind when considering whether or not to feed a resident’s eggs back to them, here). You could also consider implanting a chicken laying soft-shelled eggs to potentially give their body time to recover. Be aware that soft-shelled eggs could also be a result of an issue in the oviduct.
Egg Binding
A hen who is egg bound has an egg stuck in her oviduct. Typical signs of egg binding include obvious straining, squatting, standing up oddly tall, open-mouth breathing (from the pain and stress of pushing), and a lack of appetite, though sometimes the only sign something is wrong is that they are isolating themselves or not quite acting like themself. Egg binding can lead to cloacal prolapse, a potentially fatal condition. Do not cut the bird to get the egg out, and do not break the egg. In some instances, holding the chicken in a warm bath can help her to pass the egg. However, this doesn’t always work, so watch the chicken closely, and if she does not pass the egg while in the bath, or if her symptoms worsen at all, take her to the veterinarian as soon as possible- if left untreated, egg binding can be fatal.
If you suspect a hen is egg bound but she is not showing any of the more serious symptoms described above, you can place her in an area with a safe heat source, such as a hot water bottle, heating pad, or Snuggle Safe heat disc. Just make sure she is protected from coming into direct contact with the heat source and that the space is set up so she can choose to be close to the heat source or not. Talk to your veterinarian about providing an oral vitamin and probiotic supplement made specifically for chickens and adding additional oral calcium to her diet during this time. If, over the course of the next 24 hours, the hen has not passed an egg or if she becomes progressively painful, she should be examined by a veterinarian.
Be aware that some of the reproductive tract illnesses described above can present similar signs to egg binding and may be misdiagnosed as such. Diagnostic imagining can be used to determine the cause of an individual’s clinical signs.
What About Preventative Surgical Sterilization?
Given the fact that hens are at risk of developing a host of reproductive tract illnesses, you may wonder if you should consider surgical sterilization as a means to protect your residents from developing these issues.
As mentioned above, in female chickens, only the left ovary and oviduct is fully formed and functional. The ovary is positioned in the same area as a rooster’s testes- along their back and near the kidneys- and is attached to the abdominal cavity wall. The ovary is supplied blood primarily from the ovarian artery. In addition to arteries, there are also multiple veins associated with the ovary. One major complication when attempting to remove a hen’s ovary is its proximity to numerous blood vessels, and when life-threatening hemorrhage occurs during the procedure, it is typically venous, not arterial, bleeding, according to M. Scott Echols.
Because removal of the ovary, much like the testes, is complicated and risky, it is only advised as a response to a health issue, but due to the risks associated with the procedure, we’d recommend having a discussion with your veterinarian to determine if there are other treatments available. In the United States, this procedure is only performed by a small percentage of veterinarians. Even if your veterinarian specializes in avian medicine, they may not be willing to perform this procedure due to the amount and severity of complications that can arise.
In mature hens, removal of the entire ovary is difficult. In some cases, removal of the oviduct, instead of the ovary, or in addition to part of the ovary, may be recommended, but just as in roosters, removal of part of the reproductive tract as a means of preventing breeding or future health issues is not advised. It’s also important to note that while removal of the oviduct often causes the left ovary to regress (and stop producing follicles), this does not always happen. In these cases, the hen will continue to ovulate and will require lifelong Suprelorin implantation to prevent deadly internal laying complications.
For more information on compassionate care for chickens, check out all the the information covered in Basic Chicken Care Part One and Two!
SOURCES:
Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)
Ovarian Tumors Of The Hen (Non-Compassionate Source)
Avian Reproductive System: Female | Small And Backyard Poultry (Non-Compassionate Source)
Reproductive System | Poultry Hub (Non- Compassionate Source)
