then how to people end up with chicks? And i understand but i still think they should have their life purpose fullfilled
As I understand it, the Cornish X chicks that people buy are the product of a very specific breeding program. A very simple expalination is that there are 4 individual flocks - lets say Flocks A, B, C, and D. Roo's from Flock A are put with hens from Flock B to produce chicks A-B and Roos from Flock C are put with hens from Flock D to produce chicks C-D. The A-B roos are then put with C-D hens and the eggs from this cross are then hatched to make the Cornish Cross chicks that are sold as broilers.
This crossing of very specific birds creates a chick that has specific genetics from each of the individual starter flocks.
If you think they should have their life purpose fulfilled, then you must not be a supporter of spay and neuter for dogs and cats either?