A couple of months ago, there was a huge heated discussion
amongst the breeders on the Collie list about this very
subject of merle to merle breedings.

Quite a few of the well known breeders came out and said
although it would be a rare occurance, if they felt a
merle to merle breeding would improve their line, they
would do it. Statistically speaking they explained that only
25% of the puppies would be Double Dilutes (50% Merle
and 25% Tri) and not all of the Double Dilutes would have
any health issues. In some rare cases, they felt that the
small risk was worth improving the breed overall. If any of
the Double Dilutes had health issues, they would immediately
put them down. They absolutely would not sell any of these
puppies.

They were speaking freely about this on an open list and
didn't seem to have any fear that they would be banned
from the breed club, so I got the impression that it's not a
totally taboo thing to do.

Note though, I'm not saying I approve. Just wanted to pass
on some information that I read from the Collie breeders on
this subject.

Par...