Let's assume constant speed
35 yards is 105 feet
At 1250 fps it takes .084 sec
At 1500 fps it take .07 seconds
Difference is .014 seconds
Google says ducks fly at 80 km/h which is 22.2 m/s so in .014 seconds the duck will travel .31 meters which is about a foot in difference of position.
Many other factors involved. Is the duck flying slower, your reaction time etc.....
So increase your lead by a c**t hair. Oh and the difference in trajectory will be about .96 mm so aim a weeeeeeee bit higher too.
So if you include all other parameters and considering your spread of shot the answer is No.
Oh and for all you Physic guys out there I know I assumed constant velocity which I know is wrong.