First find how many eagle feathers he found: 17 * 6 feathers = <<17*6=102>>102 feathers
Then add the number of hawk feathers he found: 102 feathers + 6 feathers = <<102+6=108>>108 feathers
Then subtract the number of feathers Jerry gave to his sister: 108 feathers - 10 feathers = <<108-10=98>>98 feathers
Then divide that number by 2 to find how many feathers Jerry has left: 98 feathers / 2 = <<98/2=49>>49 feathers
#### 49