You do not need another breed to compare crops with. First thing in the morning, before anybody eats anything, go around and with the bird facing away from you, rub your hand down the right side of the bird's chest. Check everybody's crop to see what they feel like. The crop is located to the right of the breast bone. You can do the same thing to the left side for comparison. First thing in the morning, you should not feel any fullness or lumps. Again, compare the right side to the left side by feeling it. The bird's crop area should feel smooth.
If it is hard, it is impacted. If it is soft, it is either soured or on it's way to being soured. Free ranging on grass can cause impacted crops and soured crops. Grass is long and winds around and around to make a big ball. It then becomes hard to break down.
If this bird has a hard lump, I suggest you only offer up water, No other food for 24 hours, or until the impaction moves. IF this lump is soft and squishy, then I would suggest only damp layer feed for several days. NO free ranging or any hard foods. Layer feed only. If the bird becomes uncomfortable with a lot of liquid in the crop, it will need to come out of there. It is toxic. She will need to be vomited.
Hold her like a football in one arm, and with the other hand, hold her at the crop. Lean yourself down, leaning the bird forward ONLY, beak straight down and massage the crop. The gunk should come out. ONLY hold her like this for 5 to 7 seconds so she can breathe and tilt her back up. If you get something to come out, give the bird a 15 sec break and do it again. If nothing comes up, then you can stop. You may need to do this again later in the day, but only if the crop fills full and gushy.
You can not judge a crop during the day, unless you know how that bird eats. Some birds do stuff themselves during the day and the crop seems huge. The crop should empty after about 4 hours of not eating. So morning is the only time you can truly tell if the birds GI system is working properly.
