Help for the Swans

Some years ago when I was working for the old Central Electricity Generating Board I went to the R.S.P.C.A. West Hatch Animal Centre.
Hinkley Point Nuclear Power Station had donated liquid detergent to help clean badly oiled swans.
I went into this room that was full of steam, where three tables with two people on each were washing swans.
Much to my surprise the swans just lay on their backs and watched the cleaning with no sign of protest.
I suppose they were tired from the effects of the oil and thought resistance was futile.