I'll preface my comments by stating that I'm obviously not sure how much experience you have in buying/selling domain names for profit, aka domaining or domain investing, but unless this post is part of a larger strategy you have in place [actually, even if that is the case] this probably isn't the most ideal medium for listing your domains in hopes of finding buyers. Heck, I could be completely wrong and you could get quite lucky though, of course, but let's call that an outlier.
To increase the likelihood of a passive sale, your best bet is going to be to list your domains on as many platforms as possible, including:
And a more proactive means of selling is to actively search potential end users, aka potential buyers, who have a legitimate possibility they'll find actual value by owning the domain more than you...in which case they will hand over money in order to benefit from said value that would come with owning the domain name.
You do this by identifying potential end users [buyers] through Google. Then, use Google/Facebook/directory listings to search for contact email addresses for these leads. Then, you craft a legitimate business email template that you send from a legitimate-sounding email address -- one that has a short intro and explains that you're offering the domain for sale at X price. Generally, depending on your subject line and domain upwards of 90% will ignore your email. In which case, up to around 10% may open it, and of those, maybe 5% will actually be interested. Finally, of that 5%, maybe 1-2% will actually reply and negotiate with you. And you'll close with a potentially smaller percentage.
So it's not an easy game, but it gets easier as the quality of your domains and leads increase. If you're not getting any responses, either your domain is poor, or your ability to find suitable leads is. Or both.
Bottom line is if someone offers you more than you paid for those domains specifically, sell the domain immediately. WePurchaseAnyHouse > Dog domain as there are more potential end users. However if you can identify people or businesses who are buying lots of dogs, for some reason, then you need to contact them ASAP and advise that their dream domain has become available.
My humble opinion, of course. Wishing you the best of luck!
P.S. Visit NameBio.com to learn more about what the domain market values in terms of keywords and phrases. Lots to be learned simply from researching and watching the daily sales that are made at the various marketplaces.