。
There are animals that don't reproduce when kept in cages.
Literal
Cage [possessive-の] inside [locative-で] be-kept-[when-と] children [object-を] not-give-birth animals [also-も] exist.
A zoology observation about captive-breeding challenges. 檻 (おり) is 'cage, pen' — specifically the enclosure for larger animals (as opposed to 籠 for small bird cages). 飼われる is the passive of 飼う ('to keep (as a pet/livestock)'). 子どもを産む ('to give birth to children') uses 産む ('to give birth'). The ~と conditional expresses the generalization.