The study shows that raising rabbits for a way to fund the farm is not really feasible.  However, they DO produce some really good sets.  Since an immature bunny (pink) eats the same amount as an adult (white) and they both sell for  5,000 Coins, then you should sell the pink ones immediately only keeping a few to replace the white ones which will Retire (turn Golden) in 11 feedings.  They consume a great deal of Hay, and if on the land, ROUND Hay Bales are the best way to feed them.

WARNING...IF  you don't sell those little pinks ones off...you very SOON will have a FLOOD of little bunnies all over your land.  AND, IF you have not cleared that land...they will eat everything in sight, LOL!  SO, although that will help you clear your land...you will LOSE all that you would have gotten by clearing in yourself.