Who sang the song 'HAIR' in the musical (movie version) of the same name?

In the film version the song was sung by Woof (played by Don Dacus), the song was sung by different characters in the stage musical.

https://en.wikipedia.org/wiki/Hair_(film)

This website lists the plot with the song list. This is an excerpt

Claude returns, having passed his Army physical. Berger, Woof, and Hud try to
develop ideas for freeing him from service in Vietnam. Claude burns his
draft card, but the Tribe discovers that in fact it's his library card.
A woman and her husband (tourists in a land of hippies) talk to the group.
Claude,Berger, and the rest of the Tribe sing 'Hair' for them.
The woman, impressed, responds with 'My Conviction,' and then reveals that
she is not a 'she' at all, but a transvestite!

http://www.themusicallyrics.com/h/51-hair-lyrics/322-synopsis.html

Treat Williams character Berger sing the song hair in the movie version. However
the Cowsills put it on the billboard charts in 1969.

Hello I am Fosse4's daughter, who stage managed Hair at the Edinburgh Fringe Festival.
In the film, Berger, Claude, Woof and Jeanie get arrested, and we see Woof in prison talking to a woman. She asks him why he has long hair. He thinks: 'She asks me why, I'm such a hairy guy...' the opening line of the song 'Hair'. There follows a song and dance routine in the prison to this song.
In the stage show, Berger and the tribe meet and sing to two people who confront the hippies, Margaret Mead and Hubert.
In the film, Berger does crash Sheila's party and sing on the table, but he doesn't sing 'Hair', I think he sings 'I got life'.

Honestly not me posting before - Rachael is my daughter who gave me the information in the first place.(She stage manages the Leicestershire Youth Arts Group)

thank u brainy blonde, i thought it was the cowsills but wasn't sure made my day. thaxs