One dog can't do it all, he has to sleep sometime. Two or three dogs, maybe. They will be much more expensive and time consuming to develop as a good deterrent force than any coop upgrades, or especially that electric fence.
Mary
Until you have a very safe coop, and hopefully a small safe run, there's no way that your birds will be safe.
Electric fencing!!! Premier1supplies has great products and advice, and Howard E on this site is an excellent resource too.
Every predator imaginable will feast on your birds until...