The Crop. Just what IS a Crop, what do they do and why do birds have them?
Anatomy of a Crop:
The Crop is a muscular pouch located on the right side of a birds lower neck or upper breast area. All birds have them. Chickens are creatures that are prayed upon by many creatures. Fortunately chickens were given crops so they could go out into the field and gorge themselves, then run to cover and hide for hours digesting their meals. So you could say the Crop is a storage tank for food waiting to be digested. To feel a Crop you simply stand over the bird, beak facing away from you and you place your hand at the lower end of the neck where it meets the breast, and slide your hand down the front of the breast. The Crop is on the right side of the bird's breast.
What is the Purpose of a Crop:
And how does the Crop store food for so long without growing bacteria you ask? A healthy Crop is loaded with lots of good bacteria so when food sits in this pouch for hours on end, the good bacteria keep the food from growing toxins and harmful bacteria. As the Gizzard grinds up all the grass, weeds and roughage the bird just ate, the Crop slowly contracts and pushes small amounts of food down through the tube toward the Proventriculus or stomach, through the Gizzard and on through the Intestinal tract. When running properly, it is a very efficient system, with the Crop playing a huge roll in the entire digestive tract.
But sometimes the Crop malfunctions which causes distress, illness and sometimes death to the bird. Food and waste need to keep moving through the system for the bird to take in nutrients and expel waste. If the intestinal tract shuts down, the bird can die.
Ailments of the Crop:
"Help!...There is fluid leaking out of my birds beak and the Crop is huge!".... How many times have we seen threads started with this line in our Emergency section?! So how and why do crops go bad? Lets start with some possible reasons why Crops have issues:
Some Possible Reasons for Crops to stop functioning properly:
*The Crop has become slow
*The Crop is Sour (Candidiasis/Yeast infection)
***The bird has a bad Coccidiosis infection
*There is Canker somewhere in the system
***The Intestines are blocked by Worms (VERY common cause of slow or impacted Crops)
***The bird is Internally Laying or has Reproductive Cancer*** (Both of these are extremely common in hatchery stock and one of the more common reasons a bird turns up with a slow, sour or impacted crop. The crop issue is a symptom of these however seems to be the first symptom.)
*The Crop is Impacted
*The bird has Enteritis and or Coccidiosis (both of these, many times, go hand in hand)
*The Crop has Thread Worms
*The Crop has been injured
*There is an impaction in the Gizzard
*There is an impaction in the Intestinal Tract
*The bird is Egg Bound
*Tumors have grown around the Intestinal tract blocking the exit of waste
*The bird has Waterbelly (Ascites)
*The bird is laying internally
*The bird has some sort of internal infection
*The bird is dying
Diagnosis a Crop issue:
It is so easy for a birds intestinal flora to become out of balance. There are healthy supplies of yeast, e.coli and other bacteria in the gut at all times. Much of it is used for digestion. But hosts of things can throw the entire machine off balance and if one over grows itself, seems like the rest of it does too. And too much of these yeasts and e.coli's can be deadly. So if the diet of the bird is off even a little bit, too much starch, impactions, worms, parasites, bacterial infections, egg binding, internal laying, canker, alkaline environments (this is my issue here as my soil is loaded with molds, mildews and yeasts) wild birds can bring in disease and yeasts, genetics can play a big part, just about anything that effects the over all health or weakens the immune system of the bird and or slows down the intestinal machine will throw the entire thing off and cause an overgrowth of yeast and bacteria. And it is very difficult to figure out which came first, how they contracted it and why. Even many humans have problems with an over growth of yeast in the body. So that is why when I hear of someone having a bird with a crop issue, I always start with the basic stuff, which more often then not is the problem...worms, cocci, egg binding or overall health. Ascites is pretty apparent. Grass impactions do happen, but are not all that common as long as the bird has access to grit and is healthy to start with.
So how do you know if the bird has a crop issue? Lets start with the healthy crop. A bird that has a healthy fully functioning Crop will always wake up with an empty Crop and go to roost with a full Crop. Birds like to stuff their Crops full a few hours before roosting so they can get through the night with enough calories to stay warm and alive. It takes about 4 to 8 hours to completely empty a Crop. So upon inspection first thing in the morning before the bird has eaten or drank anything, the Crop should be completely empty. Morning is the only time you can count on a Crop to be empty with a healthy bird. Crops can feel funky all day long...soft and squishy, hard and firm. So make your assessment in the morning before the bird has eaten or drank anything. If you come to find a bird with a full crop in the morning, something is amiss with the digestion or the bird itself.
If the bird has been developing a crop issue that has gone unnoticed by you for some time, you may happen to pick up your bird and have it empty the contents of it's full crop on you, with liquid pouring out of the beak. Or sometimes you may find the bird sitting in the corner somewhere looking sick and through an inspection of the bird, you find he or she has a full crop. However remember, other illness can cause the crop to stop working. So you will need to do an overall exam of the bird to try to determine why the bird has this crop issue and what needs to be done to treat it.
Lets start with giving the bird exams. Keeping tabs on your feathered friends is always the best way to keep them in good health. Along with the Comb color, the activity level of the bird, whether he or she is eating and drinking well, regularly checking the Crop is a good way to monitor the health of your bird. Many simple issues, diseases and conditions can be prevented and or cured quickly if caught early enough. I give my birds a Crop check daily each morning before they have eaten or drank anything. And if I have a bird that is old or ailing in anyway, I check the Crop at roosting time as well. This way I know if the bird is eating enough. Crops should be full at roosting time. If they are empty, there is something going on with the bird. If there is something in the Crop in the morning, again, something is amiss. And if you are keeping regular tabs on the Crop, you could potentially save your birds life having gotten treatment going early enough.
Treating Crop Ailments
The Impacted Crop:
Sometimes it is hard to tell whether or not the bird has an impaction or a doughy crop. They are very similar in one aspect, they will be hard first thing in the morning. However when the bird drinks or you syringe water down the birds beak, a doughy crop will get soft and you can actually knead it like dough. Where as the impacted crop will remain hard all day long. Sometimes the bird will also be pooping out bits of grass or what ever has impacted it. Impactions are usually very large and very hard. Doughy crops start out small and remember, they are pliable.
So lets say you go up to the coop in the morning and you do a Crop check only to find what feels like a hard ball in "Tillie's" Crop. What is it and what do you do?! This is an impaction in the Crop. This can be a very dangerous situation if left untreated. The food in the Crop is going to start to turn toxic and could potentially kill your bird. This impaction could also be lower in the Gizzard or even in the Intestinal Tract as well.
I like to stop and think for a moment as to why this bird might have an impaction so I can properly treat the bird. Have I wormed my birds lately? Round Worms can over populate the Intestinal Tract to the point of blocking off the entire passage of waste unable to leave the bird, thus causing the Crop to become impacted. Has the bird been laying regularly and possibly is she Egg Bound, causing the Crop to become impacted? Does my bird have Ascites or a Water Belly? (This is an easy exam to do. Feel between the abdomen between the legs and up to the vent on the outside of the bird. It should be small and firm, not large, soft and squishy. Generally this is going to be a life threatening situation and most likely the bird is not going to survive. Since this article is on Crops themselves, and Ascites is it's own ailment, you will need to do more research here on BYC on treating that condition) Did my chicken get out to free ranging yesterday and into some deep long grass or some stiff vegetation? Long grass can wind around and around into a ball in the Crop and become difficult for the bird to move. This long grass or stiff foliage can cause a Gizzard impaction as well or even an Intestinal impaction. (So keep your grass cut short!) These examples are the most common reasons a Crop becomes impacted. (See below for articles treating Egg Binding and Worming your birds.)
Lets get back to this impacted Crop! So you find Tillie with a giant hard ball in her crop. And for the sake of learning how to treat this issue, lets assume she passed her exam and you feel she must have eaten a lot of long grasses or stiff vegetation yesterday while out free ranging. First thing you need to do is confine her to a cage with no food. You do not want to add to this situation since nothing is moving through her. She will not starve to death in the amount of time it takes to get this moving. Caging her will also allow you to monitor her poop output which is very important to knowing you are working this impaction out. All she can have at this time is water. Water, water and more water! Water will help to make this hard ball break down and move. If you know how to tube feed water down into her crop, please do so! This will help the impaction break down even faster. (See below for an article on Tube Feeding) She will need to remain in this cage until roosting time with only water in her cage.
Here are a couple of things you might use to get this impaction broken up and moving. Mineral Oil/Liquid Paraffin works quite well and sometimes over night. With an empty syringe, squeeze 1ml of mineral oil under the tongue in the morning, repeat at roosting time. If the impaction has not moved the next morning, repeat the morning and evening dose. Generally the crop should have cleared by the second or third day.
You can also give the bird "Crop Bound Capsules. If you don't have any Crop Bound caps you can use a stool softener. Dulcolax (Docusate Sodium 100mg. Use the plain Dulcolax only.) This stuff is stimulant free and will not cause any cramping or diarrhea. NEVER use a stool softener with a Laxative stimulant as it will cause cramping and pain. I have had great success with using Dulcolax gel caps on impacted Crops. You can also use the capsule form of the Dulcolax. It is given twice daily until crop clears. There are a couple ways to get this down the bird. I always prefer to give medications to birds via an empty syringe and shoot it down the beak. This way I know the bird is getting all the meds. Always keep some Gerber Baby Food on hand for these occasions. It makes a wonderful medium to shoot down the beak and is thick enough so as not to aspirate the bird as easily as say water. And Baby Food is loaded with healthy ingredients. Stick to the veggies and fruits verses the meat foods. This is all done without a needle. Suck up 1cc of baby food and inject it into a small cup. Then take two gel caps and prick them open. (Do not cut yourself!) Squeeze the contents in the baby food and mix well, discarding the empty caps. Spoon up this mixture and load it into the bottom of the syringe. Try to get it all. Then gently insert the plunger, trying not to shoot it all over the walls! Tap the bottom to get it down away from the tip if you have to. 1cc can be safely shot down the beak of a large bird without gagging or aspirating the bird if done properly. Any more than 1cc and you will need to shoot it down in two increments. Gently squeeze this on the birds front or middle tongue as you hold the head level. Never squeeze anything into the beak with the head back or deep into the throat. Level and on the front of the tongue. While you have the bird out, massage the crop until it feels softer. About 5 mins, gentle massaging. Then put the bird back in the cage. If you are unable to use this syringe method, you can offer up about a tablespoon full of warm, chopped up hard boiled egg. Simply squeeze the contents of these gel caps onto the egg. Mix well and discard empty capsules. Make sure she eats it all. Check for droppings every hour. During this time, give the bird another Crop massaging. If you are tubing water down the bird, do the same...crop massages after every hour of giving water and after each dose of Dolculax. If you know how to get water down a bird with a syringe without aspirating her, then please do that too. 10cc's will do wonders followed by a Crop massage every hour. I have found that after about 4 hours the pooping will start. Slow at first, but as the day wears on they start to poop more and the crop is getting smaller. Sometime in the afternoon give her another dose of Dulcolax gel caps, same method. At roosting time I let the bird roost up with her mates and at the crack of dawn I am up before she eats or drinks anything and I am checking the crop. The Crop should be empty or nearly empty. If only a tiny bit the size of a marble is still in the crop, you can keep her out of the cage for the day. No hard foods, free ranging or anything that might cause more trouble. Give her another dose of Dulcolax, same method. Monitor the ball all day and a few massages that day will also help. Later that afternoon, give her another dose of the Ducolax, same method. Check her Crop the following morning, the Crop should be completely empty and back to functioning properly. Just like the Mineral Oil, it may take 3 days using the Ducolax to clear the crop. If the bird's Crop is empty in the morning, bird can now go back to it's regularly scheduled day, however keep the diet on the light side with easy to digest foods.
What is a doughy Crop? If you find your bird has a crop full of what feels like bread dough...you can almost knead it from the outside...the contents are pliable and hold it's shape. And sometimes it is literally attached to the walls of the Crop. This is caused by a few things:
1. The Crop has become dehydrated due to a blockage and only the liquid is passing through the bird leaving all the food stuffs. The bird may also be very dehydrated from the lack of water.
2. This is a yeast infection and you are feeling the growing yeast. If you find these things early enough, one morning you might feel what seems like a marble sized ball in the bottom of the crop. The next morning the marble is the size of a peach pit. The day after that it is the size of a plum. In both cases you will be able to actually "knead" this wad of gummy dough material in the Crop.
So how do you get rid of it? I have seen this in a few birds over my years and can be difficult to treat. I have found a couple of methods to rid a bird of a doughy crop. The first method works really well on chicks that are simply dehydrated in the brooder. Its a very simple yeast and breaks down easily with the first method. The second method, the Acified Copper Sulfate works better for those adult birds that are suffering from medical issues that are causing this dough crop in the first place.
I had heard of the following method to break this gummy ball down many many years ago when I raised Cockatiels. If you don't feed baby Cocketielsl properly, they can develop this gummy doughy Crop from dehydration of improper temp of food. Usually within 24 to 72 hours, the entire mass had moved. You can find most if not all of these things in your spice pantry:
1/16 teaspoon Ginger Powder (you can even use the contents of a human Ginger capsule)
1/16 teaspoon Cinnamon Powder
1/16 teaspoon Cayenne Powder
1 teaspoon of Lemon Juice
Mix this all together and use a syringe without a needle and suck up .3 to .4ml at a time and squirt down the throat, under the tongue, HEAD LEVEL. Never give more than .4ml at a time or you can aspirate the bird, having it go down the wrong pipe. (occasionally they do aspirate if you aren't keeping the head level or used too much liquids. If only .3ml went down into the air ways, they will not die. Just let them cough it out over the next hour and be careful next time you are syringing in water.) I like to use those small insulin syringes of 1ml. You can usually get these for free at pharmacies. Get this ENTIRE mixture down the throat. This will only take a few minutes to get it all down. Massage crop and knead air up to the top slowly to burp out excess air when done. Do this 3 times a day for one or two days and the mass will dissolve within 24 to 72 hours. If you know how to tube feed, you can give this one one fell swoop through a tube 3 times a day. Of course if you are dosing a very young chick, being that their Crops are so much smaller than adult birds, you will want to use half of this dosage or less depending on the size of the bird.
**However, if this doughy crop just refuses to move, (especially in those adult birds) there could be a heavy Coccidiosis infection, Canker or even an E.coli imbalance enough to cause this huge case of Doughy, yeasty crop. I have had a few cases of Doughy crop that were so stubborn, Acidified Copper Sulfate was the only thing that got them moving. The interesting thing about ACS is that it will take care of an over growth of not only yeast, but E.coli, Cocci, Vent Gleet and Canker as well, all of which can gum a crop right up. Copper Sulfate is used in all animal feeds as a source of Copper. However in large quantities it is toxic to pretty much everything. I have never had problems using it on my birds, however make sure to use it properly, measure it out accurately and use it for on the specified amount of time. I have in the past used Fluconazole from the vet. You can buy Fish-Flucon on line 5-10 mg per pound of bird, 2 times daily for 2 to 4 weeks. Stubborn cases required adding of the yeast buster recipe too, the Cinnamon, Ginger and lemon juice mixture.
To make a batch of Acidified Copper Sulfate: 1/4 teaspoon ACS to one gallon of water. You can use a little of this for a few days, it will last that long. Change the birds water daily and give them new each day for 7 days. 10 days is max. If the bird is improving but not well at day 7, use some probiotics for a couple of days, allowing the bird to flush their system of the Copper and start back up on the Copper a couple days later and run it through them again. When the treatment is finished, make SURE to use probiotics for a week to replenish all that was lost or all this could reoccur again. Follow this with ACV a few days here and there through out the month to pickle up the intestines, pathogens have a hard time taking hold in a sour gut.**
Of course this yeasty condition usually arises because some other medical or physical issue is going on at the time. So make sure to address what is going on after you clear out the crop.
The Slow or Sour Crop:
Lets say you head up to the coop one morning only to find "Miss Molly" with a full squishy Crop. Now what do you do?! If you have been doing Crop checks each morning and this appeared out of nowhere, the Crop is not yet Soured. It is considered Slow at this point. Sour comes later after too much bad bacteria and yeast have been growing in the Crop from it emptying too slowly after a few days. Slow and Sour Crops can be caused by many things not only from the list of possibilities that I listed above, but also from simple things as feed changes, some new food that gave the bird indigestion, feed that has gone bad, moldy or buggy, and sometimes certain birds just cannot digest certain feeds. I have a hen that had a Chronic Sour Crop for years until I figured out she couldn't tolerate the feed she was on. After 4 or 5 different feeds, I finally found one she could eat without a continuous Slow or Sour Crop. So sometime a feed change is in order. Sometimes a Slow or Sour Crop is stemmed from something more serious like Ascites, some internal infection, organ failure or the bird is simply dying. Generally when a bird is near death, the Intestinal Tract has shut down and liquid is filling these cavities. The Crop will become so full it is pouring out of the beak. These types of birds are sometimes easily diagnosed as they are sitting in the corner of the coop, eyes close and barely conscious, very dark red or cherry colored comb and not responsive. In this case, the best thing you can do is move the bird to a warm soft place, heat lamp if needed and make the bird as comfortable as possible so it can gently pass away or humanly put her down.
So for the sake of this article, lets just assume that Miss Molly is not dying, she has past her exam, she has had no feed changes recently and maybe she got into something that has caused the good bacteria in her crop to diminish and she has a bit of indigestion. (The following applies to any feed changes or the need for a feed change as well.) First thing you need to do is get this gunk out of her crop. This stuff is going to become toxic very quick like and since chickens can't vomit, you will need to do it for them. If left untreated, this gunk can poison her. So take her outside for this next procedure. Hold her like a football in one arm, beak facing out. With your other hand support her at the Crop. Stand yourself with feet apart and lean yourself and the bird forward. You are going to want to lean her far down, beak facing the ground, tail up. Gently squeeze and massage the Crop. The MOMENT the fluid starts to come up out and out of the beak, hold her for no more than 2 seconds in this position and then stand her and yourself back up. Any longer and you can aspirate her. Give her a few moments to catch her breath and do it again. REMEMBER....stick to 2 seconds only in this downward position. Do this until you can't get anymore out. You will never get it all out of the Crop, but do your best so she can heal faster and feel better as well.
Take her back inside. She will need to be caged but this time she can have food and water. Many times a slow Crop stems from the good bacteria in the Crop has diminished enough to slow the Crop down. The Crop being a muscle, works in conjunction with the good bacteria in the entire system. When there is not enough of it, the first thing that happens is the Crop slows down. It can even stop completely. So keeping food in the crop is important to keep it moving and help to replace all the good bacteria that is naturally there. But you can help to replace it quicker by offering up Probiotics. I use Probiotics in my poultry's water several times a week. 70% of the immune system is in the Intestinal Tract of all animals. And keeping the Intestinal Tract full of oxygen and good bacteria keeps the immune system healthy, keeps the bad pathogens from taking hold in the Intestines which is where most of them start and keeps those Crops loaded with good bacteria for good Crop health. You can use poultry Probiotics or even the human grade probiotics. All the same stuff. Follow the directions on the package for use of poultry Probiotics. If all you have is the human grade stuff, simply empty one capsule into a plastic quart waterer, discard the empty capsule, and fill with water. Make sure to change this mixture and make new daily.
She can eat only her chicken feed. It helps to dampen it with some water. Chickens love damp chicken feed and it helps to break it down easier so as to keep the Crop moving as fast as it can in it's condition. Absolutely no hard seeds, grains, grass or hard vegetation. She can eat some warm, chopped hard boiled eggs with some yogurt on them for a treat. I am not a fan of using yogurt with Slow or Sour Crops as it can produce mucus which can slow a Crop down a bit. But it does have wonderful qualities of good bacteria and protein. So go ahead and use it sparingly if you want to.
Each morning you will need to check her Crop for fullness and vomit her if necessary. I do not like to vomit during the day. The bird needs to stay hydrated and fed. I only vomit during the day if she is leaking a lot of fluid from the beak. (Fluid leaking from the beak can also happen after a bird drinks too much water. So do not confuse over drinking of a healthy bird for a crop issue. Remember...check crops in the morning of if they are definitely sick) Keep her caged and eating damp feed only. Don't re-feed damp feed from yesterday in case it has grown bacteria so only dampen a small amount at a time for that day.
I like to use a Crop Bra during times of Slow and Sour Crop. These garments are wonderful. The constant pressure against the Crop keeps food moving through the Crop and helps to prevent Souring since the food never sits too long.
The Crop being a muscle, can stretch over time if the bird has a full Crop for months on end. It becomes what is called Pendulous. When this happens, the Crop will get so large and distended that it will be unable to empty out completely which can lead to Chronic Slow and Sour Crop for the rest of the birds life. A Crop Bra will help birds with Pendulous Crops empty their Crops and remain healthy if they continuously wear these.
If at any time her breath starts to smell badly or you are seeing white chunks in her vomit, then the Slow Crop has now become a Sour Crop. Medications will now be needed. If you turn to a veterinarian to help treat this crop issue, most likely they are going to prescribe Nystatin for this yeast/fungal infection. The problem with Nystatin is that it must come into contact with the Crop and yeast/fungal infection at all times or it renders itself useless. And because the bird needs to eat and drink during the treatment, I have never found Nystatin to be useful one bit. If you can get your vet to prescribe you Clotrimazole, then do it! This stuff is very powerful and will knock out the most powerful yeast infection a bird can have. If is often given to human babies with Thrush of the mouth with great success. However if you don't have an avian vet or they do not have this medication, you can turn to vaginal cream. Yes, sounds bizarre, but I was directed by an avian vet to use this on my Chronically Slow and Sour Crop patient. And it wasn't until I started with the vaginal cream was I able to save my bird. Monistat. (Miconazole Nitrate) or Gyne-Lotrimin contains Clotrimazole. The other ingredients are glycerin and other inert products. You can use the Generic form of this product as well. I use the 2% formula. You will need an empty syringe with no needle. Stick the tip of the syringe into the tube of vaginal cream, withdraw the plunger and squeeze the tube and suck up 1cc. You are going to give her 1cc, 3 times a day. So 1cc after her morning vomit, 1cc at noon and 1cc at roosting time. Again, squeeze it onto the tongue with the birds head level. You can also use the hard boiled egg method as described above in the Impacted Crop section of this article. Give her this cream daily, be sure to vomit her first thing each morning, along with her damp chicken feed only for one full week.The above concoction of Cinnamon, Ginger, etc....works as a wonderful yeast buster for a sour crop. I have also had great luck with Acidified Copper Sulfate in the water for 5 to 7 days. Always use the Acidified stuff you get from a poultry supply, never use anything not poultry approved. This is guaranteed to clear up the most wicked yeast infection. However just keep in mind, if something like the feed is causing this yeast infection or she has an internal infection, an internal fungal infection, Crop worms, she is Egg Bound, intestinal worms or something else is causing this Crop to be slow and sour, you will need to correct these first before you can cure your bird of this yeast infection. Once you can go two mornings with nothing in the Crop, you can assume you have cured the bird of this issue. She can then go back to her regularly scheduled day. Keep her on probiotics for one week after treatment.
Prevention of Crop Ailments:
Prevention is always the best medicine. But sometimes we miss things, the bird has gotten into things it should have, or maybe "Miss Molly" is aging and is developing Crop problems. Internal Laying and Reproductive Cancer is very common in hatchery stock and 80% of all hens will die from some sort of laying issue. There isn't anything you can do to prevent either of these issues if you keep Hatchery stock, (Heritage breeds are far less effected) but be aware that MANY crop problems are due to Internal Laying and Reproductive Cancer and the crop issues are one of the first symptoms that pops up. (any internal infections or tumors that cause swelling will block of the passage of waste through the intestines, thus backing up at the crop.)
The best thing you can do is do regular Crop checks in the mornings. The faster you find these issues, the quicker you can get your bird back on the road to good health. The longer a bird remains sick, the chances of the illness becoming more serious and likeliness of death becomes more probable.
Use Probiotics on a regular basis. As I described above, they work to keep the good bacteria alive in the entire Intestinal Tract and boost immunity.
Apple Cider Vinegar. I don't recommend this to be used on a weekly regular basis, but one week a month can help to raise the PH level of the entire body and sour up the intestines enough that pathogens have a hard time taking hold there. When a Crop is Slow or Sour, the PH of it is low. ACV does not work fast and it goes in as an acid. But as the bird digests it, it turns the body more alkaline. ACV is a nice tonic to keeping your bird healthy and the Crop in good shape. 1 Tablespoons ACV to one gallon of water. Use plastic containers only. Change and make a new batch daily. Over time, the PH of the body will rise with a once a month week long treatment of ACV. The addition of Coconut Oil and Ginger several times a week. Both are antifungal and help tone and improve intestines and digestion!
Be careful with feed changes. Just as we humans get indigestion, so do birds. Small things like this can throw off the good bacterial balance in the Crop and Intestines. So mix in new feed slowly. And if you find a bird that you just can't cure with the above techniques and think she could possibly have an issue with feed, by all means change to a new feed.
WORM your birds and keep an eye out for Coccidiosis!! I can't say enough about keeping your birds Intestines free from worm impactions. Worms will drain the life right out of a bird and can block the entire Intestinal Tract up completely.
Keep your grass cut short! That long thick grass can wind up in a crop and stop it up completely. So crop the grass short!
Keep those eggs moving with a good diet and oyster shell on the side. A stuck egg will block off the Intestinal Tract.
Avoid too many hard to digest treats. Raisins and peanuts are wonderful treats. But they can be hard to break down or contain too much sugar.
Always keep grit available at all times if the birds are kept in a run and don't have access to natural grit or sand. Grit is very important for the Gizzard to grind up all hard foods. And if you have only started free ranging your birds, start with small times out side on the grass. Gizzards are also a muscle and need to develop strength over time to be able to grind up all these hard foods.
And lastly, keep your birds on a good diet. Endless water fonts, lots of sunshine and love. Keep your facilities as clean as possible. Don't let your chickens bully each other, give them plenty of space in the coop and run and enjoy spending time with your birds! They love to see you coming with or without the goodies. So go sit with them on a regular basis and see how healthy they become in body, mind and spirit.
Please check out these articles on Egg Binding, Worming your Birds and Tube feeding to help treat your bird with a Crop Ailment:
https://www.backyardchickens.com/threads/go-team-tube-feeding-updated-12-29-2019.805728/ (Thank you casportpony for contributing this thread and info to BYC)
Or these threads:
Please feel free to post a thread in our Emergency section of our forms as well for more input...https://www.backyardchickens.com/forums/emergencies-diseases-injuries-and-cures.10/