I already explained this in another thread. In order for the harvest bonus to work, (20%,40%, etc) you have to start with a granular number. Since a chicken only dropped 1 meat, the 20% bonus couldn't give you 1.2 meat. You didn't get squat. Even for a deer or something that dropped 5 meat before it barely worked. So like we did with gasoline way back, we made it more granular. 1 Meat is now like one ounce of meat, or one meatball sized amount, so that the harvest bonus perks can work.
That said, I increased the meat x5, so your getting the same meat as before, its just different numbers. The only thing you have to do is get used to it, because before if you had 5 meat you were good to go for a day or two.
That said, I have 250 meat sitting in a box, and I never bought any perks to increase animal harvest, there is tons of meat, at least in SP for a guy who travels a ton.