Looks like perfectly normal development to me. (Although I can see that the cobs are not fully developed yet). The silk simply catches the male pollen from the 'flowers' at the top of the plant, and this sets the corn inside the cobs. This always takes some time to develop and usually you wait until the silks have turned dark brown and the cobs have swollen. Once you see the sweetcorn on the cob by pulling back the leaves, you can test it for ripeness by crushing a grain with your nail. If it begins to ooze its white sap then it's probably ready.
If the cobs are not adequately pollinated, you might find there are no grains near the top of the cob at all but only half way or so down the cob.
If poor pollination IS a problem, and it can be when you are growing only a few plants, then you must try to shake the corn when the tops are flowering on a dry sunny day to distribute the pollen on the silks. You can usually see the pollen dust when you do this.

Thank you for the advise... I will check the progress of the grains