I have a warehouse where in the middle of my city Laketown. I am trying to automate my farming so i can go off and build another city elsewhere. So far I have my carrot and wheat farms. The courier will pick up from the carrot and wheat farms and deposit them into my warehouse. I want another courier to pick wheat, seeds and carrots out of the warehouse and deliver them to my Chicken, pig and cow farms. I have a warehouse control block and a warehouse interface block. It is my understanding that the courier is suppose to interact with the interface block however he will not withdraw anything. If i want my courier to simply pick up carrots and bring them to the pig farm is it better to use fill courier or take matching?

"Fill X" will take the input size as max amount for transfer.
You can use this when you want to optimize the amount of fuel in a furnace, for example.
"Take matching" is only limited by what each slot/stack can contain in the inventory.
If you have specialized farms for each animal type, i think the "Take/Deposit match" would be more appropriate.

closing.., sounds like it was only a question anyway