If your rye isn’t thick then you probably won’t get very good results. If the rye isn’t thick then it won’t suppress the summer vegetation….aka “weeds”…. and they’ll already have a head start on what you’re trying to plant. Also, if the rye isn’t thick then you won’t have enough hay to cover your summer seed you’re trying to plant. Just keep these things in mind. A little N right now will help you push out some more hay growth from your rye. Total vegetation (biomass) produced is your main concern right now. Don't watch that rye struggle or turn yellow.....help it thrive. A lot of its benefits come from the root system it puts down as well as the above ground hay that's produced. Right now is when that root system takes off and does its thing.