I had a long conversation with a great guy here in Georgia who was in the business of raising ducks for sale to Field Trial and Hunt Test Clubs until he got out last year. It can be a good business opportunity if you have the ability to charge what it takes to actually make a profit, but those opportunities are sometimes challenging. The fact is that the rising cost of gas / diesel, as well as the associated rising feed costs mean that the price which you have to charge a club for the birds is becoming higher and higher. It is difficult to find clubs that do have the ability to pay what they birds are worth, and with that said it is going to continue to be a challenge over the coming months if the cost of gas continues to rise. This is not intended to be a political statement, but the fact of the matter is that while we consumers have continued to be asked to pay increasing prices at the pump which will filter there way through to the cost of just about everything else this administration has done nothing but find ways to put additional roadblocks in the way of small business' across the country. The duck business is no different, go there with the understanding that increased cost of doing business and increased regulation will make it more and more difficult.
But hey, if you are just looking to raise a few ducks for your own use then just ignore the previous long winded response. 20 Birds will mean about a 50 pound bag of feed every week at a cost of $15 to 17.50. Have good ventilation and drainage for the pen, and have at it.