new female betta's /together??

I have a question betta people.....
I usually see chain store female betta's in tanks together, however the ones
I got have been kept by them selves, will this pose a problem with putting
them together? I have not taken them out of their neat little custom bowls
they sell them in, with a lid and a hole in the top yet. I fed them a tiny
bit of betta gold, they all ate happily, checked them out for all the normal
things with my bright light and magnified glass, they probably feel like
they are being booked for prison, they all **seem** healthy nothing apparent
to me anyway. I just added some of the water to their bowls that i use for
all my betta's.
will there be more of a problem since they were being kept alone? I guess
even the ones i see together at some stores may just be getting put together
for the first time then, so maybe they will not be no worse for it, one
other *little* problem, i guess i did not notice this until getting home,
one of them seem to be very young about half the size of the rest, will that
be a problem will they pick on that one because of it?
thanks guys nikki