overdisp(glmmtmb_poisson)

# Overdispersion test
#
# dispersion ratio = 0.2953
# Pearson's Chi-Squared = 3104.5094
# p-value = 1.0000
#
# No overdispersion detected.


zero_count(glmmtmb_poisson)
# Observed zero-counts: 9946
# Predicted zero-counts: 9953
# Ratio: 1.00
#
# Model is overfitting zero-counts