The shell bone script of current character Ugly is
Its Pinyin is Chou3.
The twist meaning of 丑 has been disappeared long time ago, people added a Hand Radical to create new character 扭 to represent the twist. 丑 has been used in Chinese Zodiac for long time.
So character 丑 didn't mean Ugly for thousands years.
Let's see the character of Ugly from beginning.
The shell bone script of original character Ugly is
The left is a liquor jar, the right is character Ghost (Post 71). Ancient Chinese considered that drunkard is ugly.
The bronze script of the character is
The small seal script of the character is
Which is traditional character.
Its Pinyin is Chou3, exactly same as 丑 above.
We now know 醜, and 丑 , with different meanings, both have been traditional characters for 3500+ years,
In 1950s, simplification of Chinese characters, the experts decided to combine the two into one: 丑, and 醜 is abolished.
People now think that 丑 is simplified character, and 醜 is traditional character, which is wrong. Both are traditional characters, simplification makes 醜 disappeared, and 丑 takes all meanings of both characters: combination of two characters into one. 丑 had never had meaning of Ugly before 1950s, but right now it is well known that 丑 means Ugly.