When I plan my kid's parties I use many sources for kids' birthday party supplies
but my all time favorite is Birthday Express. They have such a huge selection of Party Themes
, Favor Boxes , Kids Costumes 
and now they have HUGE Wall Decals that are adorable!My theme for decorations are all set and now I just need the menu and games.
Activities:
As the guests are coming in, you can have them make doggie collar name tags. Use a large ribbon and attach a piece of cardboard to the ribbon. You can punch a hole through it and place the ribbon through it. Have the kids decorate them with drawings or with doggie stickers you can easily purchase at Walmart or Target. These can be tied gently to their wrists.
Another idea is to buy inexpensive headbands at your local dollar store, some felt, glue and glitter (optional) and the kids can make puppy ear headbands.
If you are a creative painter, purchase face paint and paint black noses, whiskers and other little playful doggie features to the kid's faces. You can also paint little doggies on their cheek if they prefer.
Games:
Draw and cut out a picture of a dog and dog tails and play pin the tail on the doggie.
Bone treasure chest - if you have a large sandbox you can hide toys in various areas and have the kids try to find them. Another choice is if you purchase a bag of sand, set up small piles in various areas of your yard and hide toys in some of the spots while the kids try to find them.
Hot bone - use a doggie play bone and instead of a potato, play hot bone.
One of the things if you are an animal lover, you can also take the opportunity to requests guests bring one item to donate to your local shelter so you are teaching your kids at the same time as having fun.
