If I were you I'd just keep 'em, lol, but since you're not me, some thoughts to consider:
a) Are you really hurting for the money? Do you need it immediately? If yes, maybe consider selling them outright.
b) Are you willing to put in the extra work for a larger payoff? No expenses or bell shortage? If yes, maybe breed em so you get more bang for your buck.
c) Do you feel it's worth your time to breed them? Do you feel the payoff is worthwhile? If not, sell outright.
d) Do you feel your efforts will be wasted if you take the lazy way out? If so, breed.
Whichever way you go, I would highly consider keeping some hybrids in storage so you can easily breed again if you ever have a change of heart, another town, or need another way to make some coin. A compromise might be breeding enough to store, and then selling off your excess outright.
In the end it comes down to how you value your time~ If you feel it's gonna be too tedious to breed em and such, and that it's not worth your while, I'd just sell 'em. But if you're in no rush, I see no reason to shortchange yourself and undervalue the work you've already put in~
Good luck with whichever way you choose~