Can sheep come into heat after being bred?

Normally when sheep are pregnant they will not come into heat. If they have come into heat after being bred it is a sign that they did not catch or have aborted the fetus.

The reason why they do not come into heat is because progesterone levels have increased, while estrogen and testosterone hormone levels decrease. After fertilization of the egg, a corpus luteum is formed, which then continues to produce progesterone and prevent further estrous cycle.