Themed hen parties have been popular in Ireland for many years. I have been to several hen parties with various themes ranging from; Play Boy Bunnies (my own), Sassy Sailors, 80's Chicks and even an Amy Winehouse hen party were 36 of us went from pub to pub in Galway City dresses in Amy Beehive wigs and black dresses.
A couple of things you should consider when "theming your hen are:
The age of the hens attending
Where will the hen party be going: eg from pub to pub
What vibe do you want to give
The Group: Consider all ages when picking the theme. Would your mother-in-law to be really want to dress up in a neon tutu or a burlesque outfit? If its a mixed age group, perhaps Downton Abby or Charleston would be more appropriate, or even an Audrey Hepburn theme.
What time of year is your hen? Do you want to be dressed in skimpy hula outfits in November or would sparkley spandx Disco Divas in afro wigs be better suited to the climate.
When I went on the Sassy Sailor hen party, the bride had sent out an email saying the dress code was white knee high socks, white tee-shirts and navy shorts, she was supplying the sailor hats and neck ties.
I was a lot curvier back then and at a size 18 I was dreading the prospect of getting into little navy shorts. The outfits looked amazing on the size 10's but not so fantastic on me.
If we had all been told to come in navy and white (anything we want) and then put on the sailor hats and neck ties we would still have the sailor theme and colour for the entire group, but everyone could have dressed "age / size appropriate" and felt more comfortable in our outfits.
The Venue: A mistake I made with my own hen party was not to think of where I was having the hen party when picking theme. The hen party was in Amsterdam and when 11 playboy bunnies dressed in little black basques, black mini skirts, bunny ears and tails started wandering around the streets of Amsterdam, we got a lot more attention then we wanted and had to quickly take off the ears and tails and button up the coats until we were safely in the reserved area of the nightclub.
Many venues are now stopping themed hen parties entering the premises, so consider where you are going before donning the flashing head boppers and carrying blow up groom. It may take from the night if you have to walk from pub to pub trying to get in. Its good to know what pubs are "hen friendly" within the town you are going and have your pubs / clubs checked out / booked in advance.
The Vibe: While a Charleston theme may give a more classy vibe and be suitable for a mixed age group, an neon 80's theme gives a more fun vibe and is excellent for a younger group hitting a nightclub!
For more ideas on theming your hen party check out Dance Divas photo gallery.