Answer
To test this, look for traits which would allow males handicapped by large feathers to survive: greater speed, greater flight muscle strength, greater speed in getting off the ground, stronger leg muscle or neck muscles for fighting predators, etc.
Work Step by Step
They key is to test whatever would allow males with larger feathers to compensate for the disadvantage. Be creative in imagining what factors could be responsible--more are possible than those given in the answer.