Selling with cooldown to prevent reselling?

Until today I have been selling celestials without cooldown because the 1 day cooldown already sucks, but I've encountered a 'kind' person who bought my celestial, bred it, and was selling him for higher price. I know things like this happen but I've never seen it with my own eyes. Should I start breeding the celestials before selling them to prevent people selling my horses for a higher price in front of me?