You can buy Alfalfa meal and/or the Alfalfa pellets that you can easily crush into powder to add to his food/slurries at any Tractor Supply store, they sell them as feed for Cattle and Horses, as well as for Rabbits, and they are pretty cheap. Just be sure that you buy Alfalfa meal or pellets that are not already "medicated", as a lot of the ones meant for livestock are already medicated with medications for parasite, such as Panacur. I don't believe the Alfalfa pellets meant for Rabbits are at all medicated, and if I remember correctly they also sell Alfalfa pellets for Rabbits at both Petco/PetSmart and even maybe at Walmart in the small animal pet section.
Alfalfa is a great replacement for the protein you will be taking away by reducing the number of live roaches he eats, as the protein in Alfalfa is very high like the roaches, but it is purine-free, which is what causes the Uric Acid to build up in his blood after he eats his roaches. You want to limit the number of roaches he eats daily and replace them with both the Alfalfa and the BSFL to keep his Uric Acid down...
As Tracie already said, he is far too small for a blood test to be done to confirm Gout, but in my opinion it's pretty clear that he does in fact have Gout, based on the swelling in multiple extremities. A very experienced Reptile Vet can do a "Fine-Needle Aspiration" to collect a tiny bit of the fluid from the swelling to look for UA crystals, but honestly I'd seriously consider just putting him on the correct dose of Allopurinol for him and see if it helps. It usually takes a few weeks of them being on the Allopurinol until you'll see drastic improvement in the swelling, pain, etc. but the good new is that if he does get drastically better after taking the Allopurinol, you'll know for certain that he does in fact have Gout. I'm very comfortable saying that he does in fact have Gout, just based on the entire picture as a whole. Gout is becoming so extremely common in Dragons, especially babies and juveniles, it's getting out of control. Someone on here took their young baby to an "exotics" vet after he exhibited the same classic symptoms of Gout, and the "exotics" vet that they took him to refused to do any testing at all, saying that "he definitely does not have Gout, he's too young and we never see Gout in Bearded Dragons unless they are much older adults".
I couldn't believe it, instead of doing any testing at all of any kind, this inexperienced "exotics" vet, who had no reptile experience at all (that was obvious, as we see new cases of young babies and juveniles with Gout every week) just decided that this poor baby dragon "Must have a bacterial infection, probably a systemic infection", which made absolutely not one bit of sense based on the months and months of time he was dealing with "localized" swelling (a systemic infection would have killed him by this time, lol), and this stupid "exotics" vet put this baby dragon on a broad-spectrum, oral Antibiotic (Baytril, of course), without doing any testing to confirm a bacterial infection, let alone one that would respond to Baytril. He could have done a simple Fine-Needle Aspiration of the swelling and then done a Culture and Sensitivity on the fluid to diagnose a bacterial infection, what strain of bacteria was causing the infection (if he had one at all, which he didn't), and what Antibiotic would work to treat this specific bacteria. This vet did nothing but put him on a Broad-Spectrum antibiotic on a "Just in Case Basis" and sent him on his way.
The problem with this is that putting a Dragon who is suffering from Gout and in the middle of an active flare-up on a strong Antibiotic can actually kill them by causing them to go into Kidney failure. And after much ado this dragon was finally given a blood test (he was a juvenile who weighed over 100grams, that seems to be the cutoff for doing a blood draw) and his Uric Acid level was 40, which is extremely high. So this is why it is extremely important that you advocate for yourself and advocate for your dragon when seeing a veterinarian who is not either a Certified Reptile Vet or at least a very experienced Reptile Specialist Vet, as it seems that unfortunately most "Exotics" Vets (which in the United States simply means they are a General Vet that is "willing" to see animals other than just Dogs and Cats, that's it, the label of being an "Exotics Vet" requires no additional education, training, or even mentoring beyond graduating from Veterinary School in the US, where as someone who calls themselves a "General Vet" is simply the same thing, they just generally refuse to even see any other types of animals other than dogs and cats, which is the responsible thing for them to do)....
Now that's not to say that there aren't a lot of veterinarians who are labeled as being "Exotics Vets" who do in fact have additional education, training, and even special internships and fellowships in Herpetology and Reptile/Amphibian Medicine, or Avian Medicine, etc. There are many "Exotics Vets" who have gotten the necessary education and experience in Reptile Medicine, they simply have not done ALL of the required education and/or training that they need in order to qualify to take the Herpetology Board Tests, or they just haven't bothered to take the Board Tests (or pass them) for one reason or another, so they can't call themselves a "Board-Certified Reptile Vet" or a "Board Certified Avian Vet", and it's very important that if you happen to find one of these uniquely qualified "Exotics Vets" that you hang onto them, but this is also the reason that you must stand your ground and advocate for your dragon and it's health. Insisting that you suspect that he is suffering from Gout and that you want him to try a month of daily Allopurinol (which will not cause him any negative effects, so why not try it as not only a way to make him better, but as a way to confirm or rule-out a diagnosis of Gout).
Just a final FYI, Allpurinol is a very common human medication that is available at any human pharmacy as a very inexpensive generic medication. Most all Certified Reptile Vets or Reptile Specialists will simply weigh your dragon and then call in a prescription for the correct dosage of Allopurinol prepared in solution so you can give it to him every day orally, and your regular human Pharmacist will prepare the correct dosage of Allopurinol in a liquid suspension for your dragon from the same Allopurinol tablets that are prescribed to people. There is no veterinary formulation of Allopurinol at all, and any veterinarian that either stocks Allopurinol in their own offices or that orders it from a Veterinary pharmaceutical company is giving their patients human-grade Allopurinol, the same brands or generics that are sold at human pharmacies.
I point this out to you because of a recent situation we ran into her at I believe the end of October/beginning of November. Now keep in mind that as attested to by several members here who have dragon's with Gout and that are taking a liquid preparation of Gout daily that they get filled at their own human pharmacy after having it called in to their own human pharmacies by their Reptile Vets, they pay at most $25 for a 2-month supply of Allopurinol for their dragons, and that's the proper dose for their dragon's once every day, and that price includes their pharmacist's preparing a liquid suspension for their dragons from the human-grade Allopurinol tablets, based on the dosage that their Reptile Vets have called in to their human pharmacies. I've seen as high as $25 for a 2-month supply (giving their dragons a single liquid dose every day for 2 months straight), and as low as $15 for the same 2-month supply...Sooooooo, lol, we had a poor soul here who's dragon was displaying classic symptoms of Gout, and long story short, their veterinarian is an "Exotics Vet", who was hesitant to diagnose Gout or even run any tests at all, but the member was persistent, calling and leaving messages for this vet daily, insisting that they were going to stop giving their dragon the Antibiotics that they prescribed "Just in Case", blah blah blah, and they really stayed on their vet's back and made her listen to them. Finally this member came on the forum and happily posted that they finally got their vet to agree to prescribe a daily liquid dose of Allopurinol, and we were very happy that this poor dragon was finally going to get the correct medication that we all knew that they needed...however, they were told that this vet "did not have any Allpurinol in the correct dosage for her very small dragon, nor was it liquid, so the vet had to order it for them, 2 months worth, and it wouldn't be shipped to the vet office for at least a week or two"...this puzzled us all, because all this vet needed to do was call in the correct dosage and quantity into the owner's personal, regular human pharmacy and they could prepare it for them and they could pick it up that day, rather than making their poor dragon suffer and wait even longer to get started on the correct medication...then we find out that this member had to I guess "Pre-Pay" for the vet to order in the correct dosage and liquid preparation of Allopurinol for her dragon, and that she had just paid $223 for a 2-month round of liquid Allopurinol!!!!
I was floored, so was Tracie, but not as floored as the poor person once other people chimed in and told her that their dragon's also had Gout and were taking a dose of liquid Allopurinol daily, and that 2 months worth of Allopurinol prepared into a liquid suspension by their own regular pharmacist cost them at most $25! Now I don't know what this vet actually paid for this Allopurinol in relation to what they charged this member, but it sure as hell was not anything close to $223! I had told her she was basically paying for the the correct dosage to be prepared and put into a liquid suspension, like she was paying for the "labor" for some veterinary pharmaceutical warehouse to prepare the prescription for her, but the more I think about it I'm sure it was just her "Exotics Vet" getting upset with her for her insisting that she take control of her dragon's medical care (and this was confirmed after she called and requested that her vet cancel that order for the Allopurinol, refund her $223, and she call the prescription in to her own local pharmacist at once so that he could prepare it and she could pick it up that day for around $20 instead of $223, lol, and she ended up picking it up that day instead of having to wait another week or two; after she made that phone call and picked up the $20 prescription at her pharmacy that very day, her "Exotics Vet" completely stopped returning her phone calls or replying to her voicemails and emails...nice vet
).
So the moral to my long rant is that you must advocate for your baby, be sure to ask any and every question you think of, and if you don't think of a question or anything else until after you've left the vet's office then you need to immediately call them and keep leaving messages until they call you back; you need to be sure to not leave your vet's office after an appointment without getting a hard-copy of EVERYTHING that happened during the visit, all of your dragon's vital signs, length, weight, etc. and then any and all of the notes made by the vet, and ESPECIALLY A COPY OF ANY AND ALL TEST RESULTS, all fecal testing results, blood work results, needle aspiration and any culture results, and a digital copy of any imaging they do including all flat x-rays and/or ultrasounds, as they can email you a digital copy of all of these imaging tests immediately, so make sure that you request that they email all x-rays, ultrasounds, CT Scans, MRI's, etc. to you immediately after they do them, and then a list of any and all Prescription Medications, Injections, Vitamin/Mineral/Supplements, Fluids, etc. that they give your dragon either while at the vet's office or as take-homes, and that they list not only the names of all of these but also the dosage and frequency...Basically, do not EVER leave your vet's office without getting a hard-copy of his entire chart that documents everything they did to him, gave him, and prescribed to him, both the paper copies and the digital files of any imaging tests, and make sure that they email them to you before you leave the office, as it's amazing how often they refuse to send them after you leave...