Very young bats tend not to move very far and can be kept in a faunarium (small plastic animal container) with a heat source (see below).
A container that is 18 x 11 x 12.5cm and lined with soft cloth or fleece is adequate for a single baby (that is not very mobile).
The bat should have sufficient space to stretch its wings.
As the bat becomes more active it will need a bigger space in which to exercise. A net/textile mesh cage, for example a medium reptarium, with a heat mat attached is appropriate.
After a period of isolation and observation, housing of the bat with others may be considered:
This will depend on the plans for release such as if babies are to be released together (but not at the original roost site) – see Ancillotto et al 2012 (see Further information, support and references),
Baby bats kept in groups tend to progress more quickly as they watch and learn from each other,
The potential disease related consequences of keeping bats together needs to be carefully considered (See Health and safety>Isolation).