Water Death

I have noticed that whenever I am playing in Minecraft, that sometimes mobs that end up in the water(squid or chickens mainly), would sometimes push up against a block and die. 

 

Which sucks, especially if one is trying to use water in a creative world when building a chicken coop, in which the chickens keep dying for mysterious reasons, lol. I did a very quick search but I didn't see anything else that was currently opened in regards to this issue.