First timer needs opinion please

Hi everyone. I have a question for a friend of mine. This is his first grow. He's growing 2 Dutch Haze from Dutch Passion and a Sleestack X Skunk (freebie). He is growing in Hempy Buckets. He is using the Fox Farms products/feeding schedule. They are 4 weeks into flowering. One of his DH is yellowing. Based on his reading, he assumes it's N deficiency. His question is, is this normal for this stage of development? We've both read that eventually the plant focuses on producing bud, pulling nutes from the fan leaves. I'm posting a pic of the DH. I'm also posting a pic of a lizard who came to visit. Any ideas if he'll harm anything? (He's gone for the moment, but in case he comes back.) Any helpful comments are appreciated.

Yep totally an N def. Yes it is normal for this to happen in the flowering stage as the plant is focusing all its resources toward bud production. Leaves at the bottom of the plant often fall off when flowering sets, don't worry.

that lizard looks pretty content up there lol. one of the cooler pics ive seen on this site for sure

Green4life nailed it. Tell him to boost his N so he doesn't lose the leaves. They *can* remain green all the way to the chop.

Thanks for the advice everyone.