Bravo, that is SUCH a great ad! I love how you said that you will not adopt out single rats and that you are also charging a fee for the rats. That is a good thing to do, because it will hopefully eliminate a lot of the riff-raff out there who would otherwise try to get "free" rodents for feeders or not be intelligent enough to know about adopting pairs only and not single rats. That is super!
These are the rules that most respectable rat breeders enforce as well (adopting only in pairs, unless the person already has a lone rat at home that they want a buddy for) and not adopting out a mixed sex pair, as well as charging a fee for the adoption.)
This is great. Also, you put out excellent information on the rats' nutritional and housing needs. I agree with the other poster too, that you need to fully check out any possible adopters to see if they have the proper home environment for rats, i.e. large enough cage, proper food, etc. Great ad!