swolllen crop and missing feathers

[tinkestral]

have 20 chicken various breed but maily RIR . They have been a group for alomost two years with out any new additions and luckily not one has died.

About six weeks ago noticed a few had swollen crops . I just moinotred it over a few days and the second week pretty much all the birds had swollen crops.
Some would go down by morning but I have four where it looks horrendous and there are bald patches where the crops are swollen too they look a sight. Now they have had maggots regauly. Our local vet isnt clued up and poultry and would probably say cull the birds. Now its been weeks and although they go up and down , more so constantly swollen I am trying work out what could be causing it so seveerly.
They have access to plenty of water.
They have laying pellets , veggies and all other scraps all though saying this I have pretty much cut most things out just to see if any of them could becausing the problem.
At a loss to be honest any thoughts guys

 

[Judy]

A large crop that doesn't go down overnight almost has to be either impacted or a sour crop. Impacted crops happen when stuff won't pass, often things like hay, straw or a lot of grass clippings. Sour crop I believe is a fungal or yeast condition in the crop. I don't know whether it is due to what they eat or some internal condition. They can also develop what I think is called pendulous crop, where the crop simply gets very large. Some people even fit them with a "crop bra," some sort of sling that keeps the crop from hanging down so far. I have no idea what causes this, either.

 

[Eggcessive]

Check out this link for crop issues: http://www.the-chicken-chick.com/2012/04/answers-from-chicken-vet-on-impacted.html