These Hatch Spawners are the root of the Chicken Cycle.
Meteorites with spores can drop on a planet and they will quickly grow into a ''Roost"
You can reasonably easy destroy Roosts, which will also reduce the amount of Chickens that can grow out of each Roost. However the Chicken Queens Anger will rise faster, so you destroying many will make her appear earlier.
Often there are extra defending Tubes around Roosts, which can do quite some damage to both land and air units. Esspecially on the harder difficulties.