Did Lorne Greene wear a toupee on bonanza? I know Pernell Roberts did on the show and his was not obvious. I was watching some episodes and it looks to me that Lorne Greene was wearing a very bad toupee in the earlier episodes mainly the first and second seasons is when i noticed it.

Here's a related anecdote from IMDb:

"During the filming of one episode, Lorne Greene was required to jump off a small ledge into a lake five feet below. Michael Landon later recalled that when Greene did the stunt, he jumped into the water feet first and went completely under, but his hair piece came off and floated on the surface of the lake. Landon and the rest of the crew watched to see what would happen. After a short while, Greene's hand shot up out of the water, grabbed the hair piece, and pulled it down. Greene emerged from the lake, wearing his hair piece slightly askew. He walked nonchalantly past the snickering crew, and went into his trailer without saying a word."

Later in the series run Dan Blocker (Hoss) also wore a hairpiece.

In the first season or two, Dan's head did have more skin showing on his head. Probably in the first of a new season he started using a wig for you see his head has a more covered look. I read he was born in 1928 so by 1965 he was 33.

Pernell Roberts looked good with a hair piece, better than he would have bald at that young age. And, Dan Blocker does seem to have more scalp covered up with hair in later seasons of the show, but to me, he also looked good with a receding hairline and bald spot from the earlier seasons.