It's all about interpreting ANSI escape sequences which does terminal not tail
itself and have to do multitail
as well.
It can be done with -cT ANSI
option:
-cT term interpret terminal-codes from file/command (for terminal type 'term')
Example:
$ multitail -cT ansi log/development.log
multiple files:
$ multitail -cT ansi log/development.log -cT ANSI log/test.log