We spent the summer WWOOFing and there is one lesson we learned more than any other. BEFORE you get animals make sure you have appropriate fencing for them! I spent hours chancing cows at one farm because the fencing was faulty.
More than fencing though make sure you have shelter, water, feed and any of their other needs in place before you get them. Often the haphazard things that get put in place after the animals have been brought in function well enough that they never get replaced with something that would function much better and save time.
As they say in the military:
Proper Planning Prevents Poor Performance