HCG is the most common hormone given. It forces sexual maturity (same as Ovaprim) but doesn't force them to breed.
HCG has a neuro-blocker that that fools the pituitary, Ovaprim does not.
HCG requires a script to get, most VETS will want to see/be a part of the process, they won't just hand it out but still doesn't make them breed, only mature.
There's so much more to this and if you want to fertilize eggs there is a way but most eggs are ruined and cannot be fertilized at extraction without first understanding what opens pores in egg and activates sperm once in contact with the egg-it's a window of about 15 seconds total that both are open and active.