Gutting is easier than a fish, everything is more sturdy. Hints: either remove the neck low at the chest first, or free up the trachea and esophagus from the neck skin and connective tissue before starting to eviscerate. Tie off if the crop isn't empty, otherwise the crop will empty. I prefer to leave my intended meals in a cage overnight with nothing but a little water before bedtime, and nothing in the morning.
Cut just through the skin around the vent, pull gently rearward a bit and free it up if needed, then tie it off.
Make a vertical cut just through the skin from the tip of the keelbone to the cut around the vent, or if skinning, you can do that now. Remove the wings at the elbows for easiest skinning.
Reach in until you are past the liver, which feels large and firm. Try to locate the crop, even further forward, and gently scoop it rearward. You want to be careful not to break the gall bladder, a lima bean sized organ on top of the liver. It's nasty.
You can stand the carcass neck upwards and let gravity help with evisceration. One the pile comes out, go back in and scrape the lungs off the ribs. Pull away any remaining bits, scrape out the adrenals along the backbone, rinse thoroughly and chill in ice water until chilled through.
Time spent making a clean job of evisceration is much better spent than in trying to clean up a mess.