Do you expect hexatriene #C_6H_8# to have multiple resonance structures?
Yes, hexatriene has multiple resonance structures.
The structure of hexa-1,3,5-triene is
We can draw many resonance contributors for hexatriene.
All but the first contributor have a separation of charge, so they are high-energy contributors and relatively unimportant.
Hexa-1,3,5-triene has only one important resonance contributor.