Calling the cows up?

I have a problem as of late, I call the cows up every morning and reward them with some sweet feed when they reach me. I keep hay in the hay rings 24/7,  this is a treat just for them and it lets me know when I call they will come. This is how I have done it for a very long time and also how dad used to do it. This is a good way to know everything is fine with them and no one crossed a fence, sick or did not come up because of giving birth, etc.
I am not sure exactly when the tables turned....but  a couple of weeks ago they started coming up before I called them for their feed, me not realizing thought well this is fine. I went ahead and gave them their feed and talked to them for a bit, you know cow talk :) anyway this went on for a few days. Now though they are coming up earlier (before I am usually even taking care of all the animals) and have started bellowing for me until I walk out and feed them, like I said I didn't mind the object is to make sure they are doing fine but.....

Rosie and Bull at the salt block,

Rosie taking a nap, we have had very warm weather! She is
only 6 months along but she has trouble laying down. Her leg
looks odd in the left of the picture, its just she is so big and
 has short legs its hard for her to get comfy, poor girl.

Then it dawned on me (sometimes things have to smack me in the head) I should have noticed earlier.....but I realized this morning.....as I again walked out to feed them after listening to them bellow for me (even with it raining and just breaking day). When did they start calling me up to get their feed? When did our roles reverse and why did it take me so long to notice? :P