What kind of kiddie pool is best?

Well this year I bought the largest Kiddie pool I could find it was solid plastic spent 15.00 on it brought it home so excited to fill it up for my flock and after I did it would collapse over on one side after filling it didn't appear to be flimsy when I bought it but apparently it was so I went back and bought another one to support the first one now it works great and my flock now have a cheap plastic pool for 30.00 dollars to play in. I think if I ever do it again I'll go look at those thick rubber stock tanks I have one but it won't accommodate very many at one time.