Why to revive extinct species and why we should not do this

 Some of you may had already know about the scientists that managed though out molecular biology to recreate dino snouts in chicken. Well even if I love the dinosaurs I think that some things are better left dead and I'm not saying this because of my religion, I'm saying this because even if genetic modification in other beings than human is let say accepted it still can have bad consequences.
 For example if we can clone all the animals from the ice age what environment could sustain them when we are destroying our ecosystems willingly and without remorse, think what this would cause:

1. lack of space needed to sustain the animals
2. ecological disasters
3. an open conflict with hunters and poachers which will force the scientists to make endless copies of the animals only for them to hunt an have trophies
4. open conflict with authorities because of the fact that some animals may escape from the special made areas of study

 This are just some of the problems that can occur from this kind of things.

 Anyway here are just two of the places were you can find infos about the subject
http://phys.org/news/2015-05-tweaking-beak-retracing-bird-dinosaur.html
http://www.livescience.com/50802-chicken-embryos-with-dinosaur-snouts-created.html