Ewe
A female pig that hasn't had a litter is called a gilt and a female that has had a litter is a sow
A female sheep is called a ewe.
A female swan is called a "pen; Here is a link to my resource. http://www.newton.dep.anl.gov/askasci/zoo00/zoo00392.htm
The male wolf is called a Brute, while the female is called a Fae. :) --- Actually, 'brute' and 'fae' are slangy terms used by people who role-play wolves and think that's the actual word for the two...