JUST LOST ONE DON'T WANT TO LOSE ANOTHER

How are they getting to the hay? If you can keep them away from that, it would be very helpful.
How many chickens do you have? Is it possible to take ALL food away from them for a 12 hour period? You can either bring them inside or maybe lock them in the coop with nothing to eat. They need to have water, just no food. What you want is for all of their crops to go down and empty in that period. The only way to do this is to withhold food. If they do go down, you're in the clear. Just keep them away from hay (don't use it as bedding, either).
If the crop doesn't go down, you will need to separate the bird and control what she eats very carefully, while giving her crop massages several times a day to make the mass go down. Feeding scrambled egg or another favorite treat with some oil can help them pass whatever is in their crop.
I have one hen that, no matter what I do, always has a big "beer gut". I can't get it to go down but it doesn't seem to bother her. She seems to be the exception, though, so try withholding the food to give their crops a chance to empty out, and let us know how it goes.
Good luck!

 

I agree the hay is the primary contributer to the impaction. Are you using it as bedding or something? If so, get rid of it!

 

Strange,I never heard of hay impaction.My hens all hang around hay and I use it for bedding.Good info though.Whats the worst case senario on that,how wouls I know if there is a problem,my birds eats so much of anything they are always full. Ill check that out though.

 

Not all chickens will eat hay, but some will and if they eat lots of large pieces they could be at risk for impaction. The full crop first thing in the morning is the key sign.

Corn shouldn't be a problem by itself. I have not heard of chickens eating their shavings, but if you have one who is consistently doing this you might look to nutritional/boredom issues that could cause that.

There are other reasons besides blockage for non-emptying crops ~ yeast or fungal infection is one I can think of. A vet would have to diagnose that, and treatment would consist of crop evacuation and administration of Nystatin 2x/day for 10 days.

 

My "local" feed store told me to use wheat straw instead of hay, because the birds won't eat it. I've used it for 5 years and no problems. Yet. *knocks on wood*

 

Straw will work and so will pine shavings. If they eat a little bit, that's ok (mine will pick at the pine shavings sometimes) but for some reason, yours like the alfalfa.
As far as the scratch, that cannot be a part of their primary diet. Think of scratch as candy. What they need to be eating (free choice, available at all times) is layer feed. You can give them scratch, especially now with the cold, but limit it to half a handful or less a day. I would probably give them less than that. The more "candy" they eat, the less good food they eat. If you like giving them a treat or hot food for the cold months, you can give them cooked oatmeal (they LOVE that) or scrambled eggs. Both can be served warm and are a healthier treat than scratch.
I'm wondering now if they are eating hay because there is something missing in their diets. Are you just feeding them the scratch?

 

My girl died last night for the same reason, bye bye hay! I'm sorry for your loss!