I'm not versed as to what is in the goat grower pellets. Does label tell you anything in simple terms? My only knowledge on grower pellets is in reference to pellets to fatten for meat intended goats. Since generally people don't eat Nigerians, I'm not thinking you need those pellets.
There's lots of opinions on goat feeding and not as much for concrete proof. What we do know is that Nigerians get fat on air.
Most people agree that goats do not need (or absolutely should not have, depending who you ask) any good amounts of grains unless they are nursing/in milk, and in the last trimester of pregnancy (and this is more so to get the rumen rraccustomed to grains.)
Goats absolutely must have long stemmed foods, hay and forages. If you are able to get your goats browsing on "weeds", excellent. Not everyone can, and two of my own goats don't seem to know what to browse for (it's usually a learned skill.) Also, one must know what a goat cannot eat of the "weeds" available.
Long stemmed hay...this takes some research in your local area to find good price, good quality, the right mixture, and a crossing of fingers to hope they'll eat it. Goats are buttheads with hay. Do expect them to waste a bunch as well.
Tractor Supply, and my local feed stores, always have bagged hay options as well. We frequently buy Timothy hay, but caution on Standlee brand, it'll make your goats all snotty and goopy eyed from the packaged up dust (they do love it though.) I have tried a HiFiber , bagged oat alfalfa, Timothy mix and my goats will eat it but would rather not. Alfalfa chaffhaye is a huge hit in my barn. Sometimes you will see spots inside that look like mold, but it's not, I promise. Chaffhaye is slightly fermented and has added cultures or enzymes or something I cannot recall, the spots are part of that.
Alfalfa is an interesting hay. Many sources tell me to give less during the first two trimesters of goat pregnancy, because too much can cause massive baby growth. I'm not sure how perfect that information is, because alfalfa is essential for goats in milk due to its calcium content. I surmise that my pregnant doe would also require much calcium, protein, and good rumen fermentation...I've been giving her a handful when I pull a serving out for my milker.
Goat minerals get even more complex and controversial...but let's start with general diet.