We were able to borrow a Pickwick rotary drum plucker for quite a while and it worked well for our needs. However the owner would not sell the unit. We saw the Feathrman Pro in use at a poultry seminar and liked the unit, and also that it was and still is American made, the price however was too steep for our budget. Always watching and doing broad searches on Craigslist, we came upon a used EZPlucker 181 with scalding units as well. The price for all was very, very good. Correctly scalded the unit does 3 birds at a time in under a minute. The unit is supposed to be capable of up to 40 pounds of carcass weight, so will easily pluck turkeys too. Generally I process 2 dozen chickens at a time by myself, start to finish takes about five hours.
I think though that with the discussion of 300 birds you would need to have additional manpower help, and additional resources for cooling down the carcass's. As our freezer space opens up we are always making ice blocks in preparation for upcoming processing day.
jeff