Artic isles ice age habitats

[marcatwolf]

My Ice Age habitats will only render 12 oils at a time. If I don't sit there and keep collecting, in other words, if I come back in 30 minutes, an hour, two hours, whatever, there will only be 12 oils to collect. Is this right? I thought they collect more as time goes on and they get bigger or fed more. The Wikia DS site states I should be earning hundreds of oils for the level dragons I have.

Thanks for any help you can give!