Cracks in new concrete pond.
 

I have just hired someone to install a pond/waterfall feature. They
used a liner (unsure of thickness) and the concrete was poured
yesterday (it looks like a min. of 3" thick), reinforced with chicken
wire. I noticed this morning that 3-4 (or more)cracks have formed.
Should I be concerned about these cracks? I know that concrete cracks,
but I am a little concerned that the cracks appeared so soon.