  We investigate and model the behaviour of split spin-squeezed Bose-Einstein
condensates (BECs) system. In such a system, a spin-polarized BEC is first
squeezed using a $ (S^z)^2 $ interaction, then are split into two separate
clouds. After the split, we consider that the particle number in each cloud
collapses to a fixed number. We show that this procedure is equivalent to
applying an interaction corresponding to squeezing each cloud individually plus
an entangling operation. We analyse the system's entanglement properties and
show that it can be detected using correlation-based entanglement criteria. The
nature of the states are illustrated by Wigner functions and have the form of a
correlated squeezed state. The conditional Wigner function shows high degrees
of non-classicality for dimensionless squeezing times beyond $ 1/\sqrt{N} $,
where $N$ is the number of particles per BEC.
