Snacking (even on chicken) could be the start of a slippery slope. I know with me, if I start snacking on a bit of chicken or ham it leads to the odd knob of cheese then the odd tomato or bit of cuecumber.
Unless you are doing AAM and you need to have your ration of meat and veg, I would try your hardest to beat the temptation.
I know it's really difficult but it's alot more difficult to do it in moderation that to completely abstain. Once you give in it may be like a green light to have just that little snack.
Try to find something else to occupy your mind. Very hard I know but if you are strict with yourself you will get much better results alot easier than if you do snack.
It's up to you at the end of the day but I know from experience that one small bite of anything that's not on your plan, invariably leads to another and another and before you know it it's running away with you. A week has passed and your gutted and wish you had been good.
Good luck and keep on drinking the water!