  We perform a comprehensive analysis of the spectral statistics of the
molecular resonances in $^{166}$Er and $^{168}$Er observed in recent ultracold
collision experiments [Frisch et al., Nature {\bf 507}, 475 (2014)] with the
aim of determining the chaoticity of this system. We calculate different
independent statistical properties to check their degree of agreement with
random matrix theory (RMT), and analyze if they are consistent with the
possibility of having missing resonances. The analysis of the short-range
fluctuations as a function of the magnetic field points to a steady increase of
chaoticity until $B \sim 30$ G. The repulsion parameter decreases for higher
magnetic fields, an effect that can be interpreted as due to missing
resonances. The analysis of long-range fluctuations allows us to be more
quantitative and estimate a $20-25\%$ fraction of missing levels. Finally, a
study of the distribution of resonance widths provides additional evidence
supporting missing resonances of small width compared with the experimental
magnetic field resolution. We conclude that further measurements with increased
resolution will be necessary to give a final answer to the problem of missing
resonances and the agreement with RMT.
