Why is my wooden chicken perch cracked?

Our wooden chicken perches are made from eucalyptus wood. Eucalyptus is a very hard and strong wood, as it's a natural material you will find some splitting along the length of the pole, this is not a defect and is part of the wood's characteristics. 

It comes untreated, you can use it straight out the box or you can use a pet safe varnish, paint or wood stain. The splitting won't hurt any chickens roosting on it.