manmade or natural?

So, I have these 2 items found them in different fields of the same farm .. they are coincidentally both indented very similarly in the back and rear sides they both appear balanced. the small one lays completely flat on the ground whereas the larger one lays flat on the surface then angles...

Hi everyone! I discovered this tubular, small rock a few years ago and stumbled across it just recently emptying some boxes, when it struck me that I really don't know much about it. It is approximately 3cm long and 1cm in diameter. Both ends are uneven but one is smoothed/eroded/soft and...