My 2 Pet dogs

Question
I took in 2 dogs in the last few months.  One is a poodle we found who looks like she is a few years old.  Recently we adopted a mail Shi Tsu (sp?) who is supposed to be about 7 months old.  A few days ago we found the 2 mating.  They live together and we have found them multiple times.  Is this hurting them?  Should I find  a friend to keep my male until she is done being in heat?

Answer
April,
there is definitely something wrong with this system I answered this last night. anyway it can be a strain on the animals and can possibly cause irritaition in the vulva and penis area.  also if a pup is conceived 3 or 4 days later than the others, his survival rate goes down because he will be 3 or 4 days younger at birth.  i would separate them now.
nancy