If their stem is kinda hard to bend or break then they are Marasmius oreades and i'm pretty sure they are.

Little brown mushrooms, a category not an Id, I feel like you want to be told they’re psycho active.(a.because you gathered them instead of taking photo in the field, and b. You brought up the cow thing... classic.

Can anyone ID these please ? Found in Buckinghamshire in the U.K. and has been raining on and off for the last few days with a big fog this morning. Field has cows in it all year round