15 Pigs

Your name is Cedrick; you’re a Ukrainian farmer with 15 pigs. Being a poor farmer in this country, you are given strange laws to abide by.

1. You must have exactly 4 pens.
2. You must have an odd number of pigs in each pen.
   How do you do it?

Answer
Place 5 pigs in each of three pens. Then put the fourth pen around the other 3. The fourth pen has all 15 pigs.