Selling a bird for less than a few thousand is definitely not worth it. You don't want to fuck with wild birds in the US. The Migratory Bird Treaty Act is one of the oldest federal conservation laws in the US and it's pretty brutal. Just picking up a feather off the ground can lead to fines. They probably won't go after you unless it's something especially egregious like a bald eagle feather. But selling an owl caught in the US without a permit is definitely enough to get the attention of the Feds.