Invisible Mobs/ Blocks wont be placed

I'm trying to build my house and I can't put down the first layer of blocks. Also theres a bunch of invisible pigs and chickens all over the place. They dont effect me directly but when I shoot my bow and arrow I end up killing one of them because the death sound will play and a uncooked ham or chicken item will appear (but no experience).

I found that when I log in and spin around as the world is loading everything in the item frames and paintings will duplicate and fall off the walls. I can collect these items and store them away, but when I log back on they items will reappear on the wall like they never fell off (thus cloning occurs) please fix this (but dont take away my 2 large chests of diamond blocks)